diff --git a/include/osmocom/gprs/rlcmac/llc_queue.h b/include/osmocom/gprs/rlcmac/llc_queue.h
index 80016e0..842969e 100644
--- a/include/osmocom/gprs/rlcmac/llc_queue.h
+++ b/include/osmocom/gprs/rlcmac/llc_queue.h
@@ -54,6 +54,8 @@ int gprs_rlcmac_llc_queue_enqueue(struct gprs_rlcmac_llc_queue *q, uint8_t *ll_p
 struct msgb *gprs_rlcmac_llc_queue_dequeue(struct gprs_rlcmac_llc_queue *q);
 uint8_t gprs_rlcmac_llc_queue_highest_radio_prio_pending(struct gprs_rlcmac_llc_queue *q);
 
+void gprs_rlcmac_llc_queue_merge_prepend(struct gprs_rlcmac_llc_queue *q, struct gprs_rlcmac_llc_queue *old_q);
+
 static inline size_t gprs_rlcmac_llc_queue_size(const struct gprs_rlcmac_llc_queue *q)
 {
 	return q->queue_size;
diff --git a/include/osmocom/gprs/rlcmac/rlcmac_enc.h b/include/osmocom/gprs/rlcmac/rlcmac_enc.h
index 406109a..298d364 100644
--- a/include/osmocom/gprs/rlcmac/rlcmac_enc.h
+++ b/include/osmocom/gprs/rlcmac/rlcmac_enc.h
@@ -29,7 +29,7 @@ enum gpr_rlcmac_append_result gprs_rlcmac_enc_append_ul_data(
 				struct gprs_rlcmac_rlc_block_info *rdbi,
 				enum gprs_rlcmac_coding_scheme cs,
 				struct msgb *llc_msg, int *offset, int *num_chunks,
-				uint8_t *data_block, bool is_final, int *count_payload);
+				uint8_t *data_block, int *count_payload);
 
 void gprs_rlcmac_rlc_data_to_ul_append_egprs_li_padding(const struct gprs_rlcmac_rlc_block_info *rdbi,
 							int *offset, int *num_chunks, uint8_t *data_block);
diff --git a/include/osmocom/gprs/rlcmac/tbf_ul.h b/include/osmocom/gprs/rlcmac/tbf_ul.h
index e5cfa91..660cf5a 100644
--- a/include/osmocom/gprs/rlcmac/tbf_ul.h
+++ b/include/osmocom/gprs/rlcmac/tbf_ul.h
@@ -40,6 +40,13 @@ struct gprs_rlcmac_ul_tbf {
 
 	/* (M)CS used to transmit uplink blocks, assigned by PCU: */
 	enum gprs_rlcmac_coding_scheme tx_cs;
+
+	/* Whether the UL TBF entered the countdown procedure (TS 44.060 9.3.1)*/
+	struct {
+		bool active;
+		uint8_t cv;
+		struct gprs_rlcmac_llc_queue *llc_queue;
+	} countdown_proc;
 };
 
 struct gprs_rlcmac_ul_tbf *gprs_rlcmac_ul_tbf_alloc(struct gprs_rlcmac_entity *gre);
diff --git a/src/rlcmac/llc_queue.c b/src/rlcmac/llc_queue.c
index 47cb1e9..3ff80d9 100644
--- a/src/rlcmac/llc_queue.c
+++ b/src/rlcmac/llc_queue.c
@@ -227,3 +227,31 @@ uint8_t gprs_rlcmac_llc_queue_highest_radio_prio_pending(struct gprs_rlcmac_llc_
 	OSMO_ASSERT(prioq);
 	return prioq->radio_prio;
 }
+
+/* Merge old_q messages into q, prepending them. old_q must be freed by the caller. */
+void gprs_rlcmac_llc_queue_merge_prepend(struct gprs_rlcmac_llc_queue *q, struct gprs_rlcmac_llc_queue *old_q)
+{
+	unsigned int i, j;
+
+	/* Nothing to do: */
+	if (old_q->queue_size == 0)
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(old_q->pq); i++) {
+		for (j = 0; j < ARRAY_SIZE(old_q->pq[i]); j++) {
+			struct llist_head *old_pq = &old_q->pq[i][j].queue;
+			struct llist_head *pq = &q->pq[i][j].queue;
+			struct llist_head *it;
+
+			/* Remove from old_pq and prepend to pq: */
+			while ((it = old_pq->next) != old_pq)
+				llist_move(it, pq);
+		}
+	}
+
+	q->queue_size += old_q->queue_size;
+	q->queue_octets += old_q->queue_octets;
+
+	old_q->queue_size = 0;
+	old_q->queue_octets = 0;
+}
diff --git a/src/rlcmac/rlcmac_enc.c b/src/rlcmac/rlcmac_enc.c
index 1c849a1..1e10d3a 100644
--- a/src/rlcmac/rlcmac_enc.c
+++ b/src/rlcmac/rlcmac_enc.c
@@ -67,12 +67,13 @@ enum gpr_rlcmac_append_result gprs_rlcmac_enc_append_ul_data(
 				struct gprs_rlcmac_rlc_block_info *rdbi,
 				enum gprs_rlcmac_coding_scheme cs,
 				struct msgb *llc_msg, int *offset, int *num_chunks,
-				uint8_t *data_block, bool is_final, int *count_payload)
+				uint8_t *data_block, int *count_payload)
 {
 	int chunk;
 	int space;
 	struct gprs_rlcmac_rlc_li_field *li;
 	uint8_t *delimiter, *data, *e_pointer;
+	const bool is_final = rdbi->cv == 0;
 
 	data = data_block + *offset;
 	delimiter = data_block + *num_chunks;
@@ -117,7 +118,6 @@ enum gpr_rlcmac_append_result gprs_rlcmac_enc_append_ul_data(
 			*count_payload = space;
 		*offset = rdbi->data_len;
 		(*num_chunks)++;
-		rdbi->cv = 0;
 		return GPRS_RLCMAC_AR_COMPLETED_BLOCK_FILLED;
 	}
 	/* if chunk would fit exactly in space left */
@@ -191,7 +191,6 @@ enum gpr_rlcmac_append_result gprs_rlcmac_enc_append_ul_data(
 	/* if we don't have more LLC frames */
 	if (is_final) {
 		LOGRLCMAC(LOGL_DEBUG, "-- Final block, so we done.\n");
-		rdbi->cv = 0;
 		return GPRS_RLCMAC_AR_COMPLETED_BLOCK_FILLED;
 	}
 	/* we have no space left */
diff --git a/src/rlcmac/tbf_ul.c b/src/rlcmac/tbf_ul.c
index b38c750..6bea79e 100644
--- a/src/rlcmac/tbf_ul.c
+++ b/src/rlcmac/tbf_ul.c
@@ -72,6 +72,13 @@ void gprs_rlcmac_ul_tbf_free(struct gprs_rlcmac_ul_tbf *ul_tbf)
 	if (!ul_tbf)
 		return;
 
+	if (ul_tbf->countdown_proc.llc_queue) {
+		gprs_rlcmac_llc_queue_merge_prepend(ul_tbf->tbf.gre->llc_queue,
+						    ul_tbf->countdown_proc.llc_queue);
+		gprs_rlcmac_llc_queue_free(ul_tbf->countdown_proc.llc_queue);
+		ul_tbf->countdown_proc.llc_queue = NULL;
+	}
+
 	if (ul_tbf->tbf.gre->ul_tbf == ul_tbf)
 		ul_tbf->tbf.gre->ul_tbf = NULL;
 
@@ -146,7 +153,7 @@ bool gprs_rlcmac_ul_tbf_can_request_new_ul_tbf(const struct gprs_rlcmac_ul_tbf *
 		return false;
 
 	/* the mobile station has new data to transmit */
-	if (!gprs_rlcmac_ul_tbf_have_data(ul_tbf))
+	if (!gprs_rlcmac_entity_have_tx_data_queued(ul_tbf->tbf.gre))
 		return false;
 
 	/* "the mobile station has no other ongoing downlink TBFs */
@@ -312,8 +319,12 @@ free_ret:
 
 bool gprs_rlcmac_ul_tbf_have_data(const struct gprs_rlcmac_ul_tbf *ul_tbf)
 {
-	return (ul_tbf->llc_tx_msg && msgb_length(ul_tbf->llc_tx_msg) > 0) ||
-	       gprs_rlcmac_entity_have_tx_data_queued(ul_tbf->tbf.gre);
+	if (ul_tbf->llc_tx_msg && msgb_length(ul_tbf->llc_tx_msg) > 0)
+		return true;
+	if (ul_tbf->countdown_proc.active)
+		return gprs_rlcmac_llc_queue_size(ul_tbf->countdown_proc.llc_queue) > 0;
+	else
+		return gprs_rlcmac_entity_have_tx_data_queued(ul_tbf->tbf.gre);
 }
 
 bool gprs_rlcmac_ul_tbf_shall_keep_open(const struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_rlcmac_rts_block_ind *bi)
@@ -331,13 +342,20 @@ bool gprs_rlcmac_ul_tbf_shall_keep_open(const struct gprs_rlcmac_ul_tbf *ul_tbf,
 void gprs_rlcmac_ul_tbf_schedule_next_llc_frame(struct gprs_rlcmac_ul_tbf *ul_tbf)
 {
 	struct osmo_gprs_rlcmac_prim *rlcmac_prim_tx;
+	struct gprs_rlcmac_llc_queue *llc_queue;
 
 	if (ul_tbf->llc_tx_msg && msgb_length(ul_tbf->llc_tx_msg))
 		return;
 
 	msgb_free(ul_tbf->llc_tx_msg);
+
+	if (ul_tbf->countdown_proc.active)
+		llc_queue = ul_tbf->countdown_proc.llc_queue;
+	else
+		llc_queue = ul_tbf->tbf.gre->llc_queue;
+
 	/* dequeue next LLC frame, if any */
-	ul_tbf->llc_tx_msg = gprs_rlcmac_llc_queue_dequeue(ul_tbf->tbf.gre->llc_queue);
+	ul_tbf->llc_tx_msg = gprs_rlcmac_llc_queue_dequeue(llc_queue);
 	if (!ul_tbf->llc_tx_msg)
 		return;
 
@@ -354,9 +372,188 @@ void gprs_rlcmac_ul_tbf_schedule_next_llc_frame(struct gprs_rlcmac_ul_tbf *ul_tb
 	gprs_rlcmac_prim_call_up_cb(rlcmac_prim_tx);
 }
 
+/* TS 44.060 9.3.1.1 Countdown procedure */
+struct blk_count_state {
+	const struct gprs_rlcmac_ul_tbf *ul_tbf;
+	uint8_t blk_data_len; /* length of usable data block (single data unit w/o header) */
+	uint8_t bs_cv_max;
+	uint8_t nts;
+	uint8_t k;
+	uint8_t nts_x_k;
+	unsigned blk_count;
+	uint8_t offset; /* offset in bytes in the current blk */
+	bool extra_li0; /* if last appended chunk is an LI=0 case */
+};
+static void blk_count_state_init(struct blk_count_state *st, const struct gprs_rlcmac_ul_tbf *ul_tbf)
+{
+	OSMO_ASSERT(ul_tbf->cur_alloc.num_ts > 0);
+	memset(st, 0, sizeof(*st));
+	st->ul_tbf = ul_tbf;
+	st->blk_data_len = gprs_rlcmac_mcs_max_data_block_bytes(ul_tbf->tx_cs);
+	st->bs_cv_max = g_rlcmac_ctx->si13ro.u.PBCCH_Not_present.GPRS_Cell_Options.BS_CV_MAX;
+	st->nts = ul_tbf->cur_alloc.num_ts;
+	st->blk_count = 0;
+	st->offset = 0;
+
+	if (gprs_rlcmac_ul_tbf_in_contention_resolution(ul_tbf))
+		st->blk_data_len -= 4;
+
+	switch (ul_tbf->tx_cs) {
+	case GPRS_RLCMAC_MCS_7:
+	case GPRS_RLCMAC_MCS_8:
+	case GPRS_RLCMAC_MCS_9:
+		st->k = 2;
+		break;
+	default:
+		st->k = 1;
+	}
+	st->nts_x_k = st->nts * st->k;
+}
+
+static inline unsigned blk_count_to_x(const struct blk_count_state *st)
+{
+	if (st->blk_count == 0)
+		return 0;
+	return (st->blk_count + (st->nts_x_k - 1) - 1) / st->nts_x_k;
+}
+
+static void blk_count_append_llc(struct blk_count_state *st, unsigned int llc_payload_len)
+{
+	int chunk = llc_payload_len;
+	int space = st->blk_data_len - st->offset;
+	OSMO_ASSERT(st->offset < st->blk_data_len);
+
+	if (chunk == 0)
+		return; /* Should not happen in here? */
+
+	/* reset flag: */
+	st->extra_li0 = false;
+
+	/* if chunk will exceed block limit */
+	if (chunk > space) {
+		st->blk_count++;
+		st->offset = 0;
+		chunk -= space;
+		blk_count_append_llc(st, chunk);
+		return;
+	}
+	if (chunk == space) {
+		st->blk_count++;
+		st->offset = 0;
+		chunk -= space - 1; /* Extra LI=0 */
+		blk_count_append_llc(st, chunk);
+		/* case is_final==true (CV==0) has no extra LI=0. Store the
+		 * context to subtract if this was the last step. */
+		st->extra_li0 = true;
+		return;
+	}
+	/* chunk < space */
+	/* Append a new LI byte */
+	st->offset++;
+	st->offset += chunk;
+	if (st->blk_data_len - st->offset == 0) {
+		st->blk_count++;
+		st->offset = 0;
+	}
+}
+
+/* Returned as early return from function when amount of RLC blocks goes clearly over BS_CV_MAX */
+#define BLK_COUNT_TOOMANY 0xff
+/* We cannot early-check if extra_li0=true, since there may temporarily have too many rlc blocks: */
+#define BLK_COUNT_EARLY_CHECK_TOOMANY(st) (!(st)->extra_li0) && blk_count_to_x(st) > (st)->bs_cv_max)
+static uint8_t blk_count_append_llc_prio_queue(struct blk_count_state *st, const struct gprs_llc_prio_queue *pq)
+{
+	struct msgb *msg;
+
+	llist_for_each_entry(msg, &pq->queue, list) {
+		blk_count_append_llc(st, msgb_l2len(msg));
+		/* We cannot early-check if extra_li0=true, since there may temporarily have too many rlc blocks. */
+		if (BLK_COUNT_EARLY_CHECK_TOOMANY(st)
+			return BLK_COUNT_TOOMANY; /* early return, not entering countdown procedure */
+	}
+	return 0;
+}
+
+/* return BLK_COUNT_TOOMANY: not entering countdown procedure, X > BS_CV_MAX.
+_* return 0: check blk_count_to_x(st) */
+static uint8_t gprs_rlcmac_ul_tbf_calculate_cv(const struct gprs_rlcmac_ul_tbf *ul_tbf)
+{
+	struct blk_count_state st;
+	const struct gprs_rlcmac_llc_queue *q = ul_tbf->tbf.gre->llc_queue;
+	unsigned int i, j;
+	unsigned x;
+
+	blk_count_state_init(&st, ul_tbf);
+
+	/* TODO: Here we could do an heuristic optimization by doing a rough calculation
+	 * using gprs_rlcmac_llc_queue_size() and gprs_rlcmac_llc_queue_octets()
+	 * for cases were we are clearly above BS_CV_MAX. This is specially useful
+	 * when the LLC queue is long since we skip iterating counting lots of
+	 * data.
+	 * if (blk_count_herustic_toomany(&st))
+	 *	return 15;
+	 */
+
+	/* First of all, the current LLC frame in progress: */
+	if (ul_tbf->llc_tx_msg) {
+		blk_count_append_llc(&st, msgb_length(ul_tbf->llc_tx_msg));
+		if (BLK_COUNT_EARLY_CHECK_TOOMANY(&st)
+			goto done; /* early return, not entering countdown procedure */
+	}
+
+	for (i = 0; i < ARRAY_SIZE(q->pq); i++) {
+		for (j = 0; j < ARRAY_SIZE(q->pq[i]); j++) {
+			int rc;
+			if (llist_empty(&q->pq[i][j].queue))
+				continue;
+			rc = blk_count_append_llc_prio_queue(&st, &q->pq[i][j]);
+			if (rc == BLK_COUNT_TOOMANY)
+				goto done; /* early return, not entering countdown procedure */
+		}
+	}
+
+done:
+	/* In final block (CV==0), a chunk filling exactly an RLC block doesn't
+	 * have the LI=0 and 2 bytes (1 LI + 1 data) spanning next block. Fix calculation: */
+	if (st.extra_li0) {
+		OSMO_ASSERT(st.offset == 2);
+		st.offset -= 2;
+	}
+	/* Remaining one would already be a block. Include it before calculating "X": */
+	if (st.offset > 0) {
+		st.blk_count++;
+		st.offset = 0;
+	}
+	x = blk_count_to_x(&st);
+	return x <= st.bs_cv_max ? (uint8_t)x : 15;
+}
+
+static void gprs_rlcmac_ul_tbf_steal_llc_queue_from_gre(struct gprs_rlcmac_ul_tbf *ul_tbf)
+{
+	ul_tbf->countdown_proc.llc_queue = ul_tbf->tbf.gre->llc_queue;
+	ul_tbf->tbf.gre->llc_queue = gprs_rlcmac_llc_queue_alloc(ul_tbf->tbf.gre);
+}
+
+static void gprs_rlcmac_ul_tbf_check_countdown_proc(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_rlcmac_rts_block_ind *bi)
+{
+
+	if (ul_tbf->countdown_proc.active)
+		return;
+	ul_tbf->countdown_proc.cv = gprs_rlcmac_ul_tbf_calculate_cv(ul_tbf);
+	if (ul_tbf->countdown_proc.cv < 15) {
+		if (gprs_rlcmac_ul_tbf_shall_keep_open(ul_tbf, bi)) {
+			LOGPTBFUL(ul_tbf, LOGL_INFO, "Delaying start Countdown procedure CV=%u\n", ul_tbf->countdown_proc.cv);
+			ul_tbf->countdown_proc.cv = 15;
+			return;
+		}
+		LOGPTBFUL(ul_tbf, LOGL_DEBUG, "Entering Countdown procedure CV=%u\n", ul_tbf->countdown_proc.cv);
+		ul_tbf->countdown_proc.active = true;
+		gprs_rlcmac_ul_tbf_steal_llc_queue_from_gre(ul_tbf);
+	}
+}
+
 static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_rlcmac_rts_block_ind *bi, enum gprs_rlcmac_coding_scheme cs)
 {
-	struct gprs_rlcmac_llc_queue *llc_queue = ul_tbf->tbf.gre->llc_queue;
 	const uint16_t bsn = gprs_rlcmac_rlc_ul_window_v_s(ul_tbf->ulw);
 	struct gprs_rlcmac_rlc_block *blk;
 	struct gprs_rlcmac_rlc_block_info *rdbi;
@@ -365,6 +562,8 @@ static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_r
 	int write_offset = 0;
 	enum gpr_rlcmac_append_result ar;
 
+	gprs_rlcmac_ul_tbf_check_countdown_proc(ul_tbf, bi);
+
 	if (!ul_tbf->llc_tx_msg || msgb_length(ul_tbf->llc_tx_msg) == 0)
 		gprs_rlcmac_ul_tbf_schedule_next_llc_frame(ul_tbf);
 	OSMO_ASSERT(ul_tbf->llc_tx_msg);
@@ -391,7 +590,7 @@ static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_r
 	rdbi->data_len = block_data_len;
 
 	rdbi->ti = gprs_rlcmac_ul_tbf_in_contention_resolution(ul_tbf);
-	rdbi->cv = 15; /* Final Block Indicator, set late, if true */
+	rdbi->cv = ul_tbf->countdown_proc.cv--;
 	rdbi->bsn = bsn; /* Block Sequence Number */
 	rdbi->e = 1; /* Extension bit, maybe set later (1: no extension) */
 
@@ -407,7 +606,6 @@ static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_r
 	}
 
 	do {
-		bool is_final;
 		int payload_written = 0;
 
 		if (msgb_length(ul_tbf->llc_tx_msg) == 0) {
@@ -424,14 +622,6 @@ static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_r
 					  "LLC queue completely drained and there's "
 					  "still %d free bytes in rlcmac data block\n", space);
 
-				/* We may need to update fbi in header here
-				 * since ul_tbf->last_ul_drained_fn was updated above
-				 * Specially important when X2031 is 0. */
-				is_final = gprs_rlcmac_llc_queue_size(llc_queue) == 0 &&
-					   !gprs_rlcmac_ul_tbf_shall_keep_open(ul_tbf, bi);
-				if (is_final)
-					rdbi->cv = 0;
-
 				if (gprs_rlcmac_mcs_is_edge(cs)) {
 					/* in EGPRS there's no M bit, so we need
 					 * to flag padding with LI=127 */
@@ -442,12 +632,8 @@ static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_r
 			}
 		}
 
-		is_final = gprs_rlcmac_llc_queue_size(llc_queue) == 0 &&
-			   !gprs_rlcmac_ul_tbf_shall_keep_open(ul_tbf, bi);
-
-		ar = gprs_rlcmac_enc_append_ul_data(rdbi, cs, ul_tbf->llc_tx_msg,
-						    &write_offset, &num_chunks, data,
-						    is_final, &payload_written);
+		ar = gprs_rlcmac_enc_append_ul_data(rdbi, cs, ul_tbf->llc_tx_msg, &write_offset,
+						    &num_chunks, data, &payload_written);
 
 		if (ar == GPRS_RLCMAC_AR_NEED_MORE_BLOCKS)
 			break;
@@ -460,8 +646,8 @@ static int create_new_bsn(struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_r
 		gprs_rlcmac_ul_tbf_schedule_next_llc_frame(ul_tbf);
 	} while (ar == GPRS_RLCMAC_AR_COMPLETED_SPACE_LEFT);
 
-	LOGPTBFUL(ul_tbf, LOGL_DEBUG, "data block (BSN %d, %s): %s\n",
-		  bsn, gprs_rlcmac_mcs_name(blk->cs_last),
+	LOGPTBFUL(ul_tbf, LOGL_DEBUG, "data block (BSN=%d, %s, CV=%u): %s\n",
+		  bsn, gprs_rlcmac_mcs_name(blk->cs_last), rdbi->cv,
 		  osmo_hexdump(blk->buf, block_data_len));
 	/* raise send state and set ack state array */
 	gprs_rlcmac_rlc_v_b_mark_unacked(&ul_tbf->ulw->v_b, bsn);
@@ -850,8 +1036,8 @@ static struct msgb *create_ul_acked_block(struct gprs_rlcmac_ul_tbf *ul_tbf,
 		rdbi->bsn = bsn;
 		is_final = is_final || rdbi->cv == 0;
 
-		LOGPTBFUL(ul_tbf, LOGL_DEBUG, "Copying data unit %d (BSN %d)\n",
-			  data_block_idx, bsn);
+		LOGPTBFUL(ul_tbf, LOGL_DEBUG, "Copying data unit %d (BSN=%d CV=%d)\n",
+			  data_block_idx, bsn, rdbi->cv);
 
 		gprs_rlcmac_rlc_copy_from_aligned_buffer(&rlc, data_block_idx, msg_data, block_data);
 	}
diff --git a/tests/rlcmac/rlcmac_prim_test.c b/tests/rlcmac/rlcmac_prim_test.c
index c8d1616..ba06fab 100644
--- a/tests/rlcmac/rlcmac_prim_test.c
+++ b/tests/rlcmac/rlcmac_prim_test.c
@@ -934,6 +934,71 @@ static void test_ul_tbf_last_data_cv0_retrans_max(void)
 	cleanup_test();
 }
 
+/* 9.3.1 Countdown procedure */
+static void test_ul_tbf_countdown_procedure(void)
+{
+	struct osmo_gprs_rlcmac_prim *rlcmac_prim;
+	int rc;
+
+	printf("=== %s start ===\n", __func__);
+	prepare_test();
+	uint32_t tlli = 0x2342;
+	uint8_t ul_tfi = 0;
+	uint8_t ts_nr = 7;
+	uint8_t usf = 0;
+	uint32_t rts_fn = 4;
+	uint8_t bs_cv_max = 4;
+	unsigned int i;
+	RlcMacDownlink_t dl_block;
+	struct msgb *llc_msg = msgb_alloc(200, "llc_msg");
+	Ack_Nack_Description_t *ack_desc = &dl_block.u.Packet_Uplink_Ack_Nack.u.PU_AckNack_GPRS_Struct.Ack_Nack_Description;
+
+	/* Submit an SI13 with bs_cv_max: */
+	rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_ccch_data_ind(0, create_si13(bs_cv_max));
+	rc = osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
+	OSMO_ASSERT(rc == 0);
+
+
+	/* Submit LLC bytes */
+	msgb_put(llc_msg, msgb_tailroom(llc_msg));
+	memset(msgb_data(llc_msg), 0xab, msgb_length(llc_msg));
+	rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_grr_unitdata_req(tlli, msgb_data(llc_msg), msgb_length(llc_msg));
+	rlcmac_prim->grr.unitdata_req.sapi = OSMO_GPRS_RLCMAC_LLC_SAPI_SNDCP3;
+	rc = osmo_gprs_rlcmac_prim_upper_down(rlcmac_prim);
+
+	ccch_imm_ass_pkt_ul_tbf_normal[7] = last_rach_req_ra; /* Update RA to match */
+	rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_ccch_data_ind(0, ccch_imm_ass_pkt_ul_tbf_normal);
+	rc = osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
+	OSMO_ASSERT(rc == 0);
+
+	/* Trigger transmission of LLC data (first part) */
+	rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_pdch_rts_ind(ts_nr, rts_fn, usf);
+	rc = osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
+	OSMO_ASSERT(rc == 0);
+
+	/* PCU acks it: */
+	ul_ack_nack_init(&dl_block, ul_tfi, GPRS_RLCMAC_CS_2);
+	ack_desc->STARTING_SEQUENCE_NUMBER = 1;
+	ack_desc->FINAL_ACK_INDICATION = 0;
+	ul_ack_nack_mark(ack_desc, 0, true);
+	rlcmac_prim = create_dl_ctrl_block(&dl_block, ts_nr, rts_fn);
+	rc = osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
+	OSMO_ASSERT(rc == 0);
+
+	for (i = 0; i < 6; i++) {
+		rts_fn = fn_next_block(rts_fn);
+		printf("RTS %u: FN=%u\n", i, rts_fn);
+		/* Trigger transmission of LLC data (GMM Attach) (second part) */
+		rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_pdch_rts_ind(ts_nr, rts_fn, usf);
+		rc = osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
+		OSMO_ASSERT(rc == 0);
+	}
+
+	printf("=== %s end ===\n", __func__);
+	msgb_free(llc_msg);
+	cleanup_test();
+}
+
 /* PCU allocates a DL TBF through PCH ImmAss for MS (when in packet-idle) */
 static void test_dl_tbf_ccch_assign(void)
 {
@@ -1128,6 +1193,7 @@ int main(int argc, char *argv[])
 	test_ul_tbf_n3104_timeout();
 	test_ul_tbf_t3182_timeout();
 	test_ul_tbf_last_data_cv0_retrans_max();
+	test_ul_tbf_countdown_procedure();
 	test_ul_tbf_request_another_ul_tbf();
 	test_dl_tbf_ccch_assign();
 	test_dl_tbf_ccch_assign_requests_ul_tbf_pacch();
diff --git a/tests/rlcmac/rlcmac_prim_test.err b/tests/rlcmac/rlcmac_prim_test.err
index a02739a..120458a 100644
--- a/tests/rlcmac/rlcmac_prim_test.err
+++ b/tests/rlcmac/rlcmac_prim_test.err
@@ -23,10 +23,10 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=33)
 DLGLOBAL DEBUG -- Chunk with length 33 larger than space (26) left in block: copy only remaining space, and we are done
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 0, CS-2): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=15): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -35,13 +35,14 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) N3104 inc (1)
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
 DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 1, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Entering Countdown procedure CV=0
 DLGLOBAL DEBUG -- Chunk with length 7 is less than remaining space (26): add length header to delimit LLC frame
 DLGLOBAL DEBUG -- Final block, so we done.
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Complete UL frame, len=0
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 1, CS-2): 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=1, CS-2, CV=0): 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 01 02 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: state_chg to FINISHED
@@ -185,10 +186,10 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=33)
 DLGLOBAL DEBUG -- Chunk with length 33 larger than space (26) left in block: copy only remaining space, and we are done
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 0, CS-2): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=15): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -220,7 +221,7 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -252,7 +253,7 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -284,7 +285,7 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -326,10 +327,10 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=33)
 DLGLOBAL DEBUG -- Chunk with length 33 larger than space (26) left in block: copy only remaining space, and we are done
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 0, CS-2): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=15): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -338,13 +339,14 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) N3104 inc (1)
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
 DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 1, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Entering Countdown procedure CV=0
 DLGLOBAL DEBUG -- Chunk with length 7 is less than remaining space (26): add length header to delimit LLC frame
 DLGLOBAL DEBUG -- Final block, so we done.
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Complete UL frame, len=0
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 1, CS-2): 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=1, CS-2, CV=0): 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 01 02 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: state_chg to FINISHED
@@ -355,7 +357,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 0, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) N3104 inc (3)
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
@@ -363,7 +365,7 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 01 02 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=1
@@ -374,7 +376,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 0, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) N3104 inc (5)
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
@@ -382,7 +384,7 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 01 02 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=2
@@ -393,7 +395,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 0, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) N3104 inc (7)
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
@@ -401,7 +403,7 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 01 02 1d 00 00 23 42 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=3
@@ -412,7 +414,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 0, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL NOTICE TBF(UL:NR-0:TLLI-00002342) N3104_MAX (9) reached
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event N3104_MAX
@@ -466,10 +468,10 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=33)
 DLGLOBAL DEBUG -- Chunk with length 33 larger than space (26) left in block: copy only remaining space, and we are done
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 0, CS-2): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=15): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -486,13 +488,14 @@ DLGLOBAL INFO UL_TBF{FLOW}: Received Event RX_UL_ACK_NACK
 DLGLOBAL INFO UL_TBF{FLOW}: Contention resolution succeeded, stop T3166
 DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 1, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Entering Countdown procedure CV=0
 DLGLOBAL DEBUG -- Chunk with length 7 is less than remaining space (30): add length header to delimit LLC frame
 DLGLOBAL DEBUG -- Final block, so we done.
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Complete UL frame, len=0
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 1, CS-2): 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=1, CS-2, CV=0): 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: Last UL block sent (CV=0), start T3182
@@ -529,10 +532,10 @@ DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=33)
 DLGLOBAL DEBUG -- Chunk with length 33 larger than space (26) left in block: copy only remaining space, and we are done
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 0, CS-2): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=15): 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 00 00 00 00 71 62 f2 24 6c 84 44 04 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -549,13 +552,14 @@ DLGLOBAL INFO UL_TBF{FLOW}: Received Event RX_UL_ACK_NACK
 DLGLOBAL INFO UL_TBF{FLOW}: Contention resolution succeeded, stop T3166
 DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 1, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Entering Countdown procedure CV=0
 DLGLOBAL DEBUG -- Chunk with length 7 is less than remaining space (30): add length header to delimit LLC frame
 DLGLOBAL DEBUG -- Final block, so we done.
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Complete UL frame, len=0
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 1, CS-2): 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=1, CS-2, CV=0): 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: Last UL block sent (CV=0), start T3182
@@ -566,7 +570,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 1, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=1
@@ -577,7 +581,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 1, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=2
@@ -588,7 +592,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 1, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=3
@@ -599,7 +603,7 @@ DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Restarting at BSN 1, because all block
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Resending BSN 1
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FINISHED}: Received Event LAST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FINISHED}: Data block with CV=0 retransmit attempts=4
@@ -611,6 +615,8 @@ DLGLOBAL DEBUG Tx to lower layers: L1CTL-CFG_UL_TBF.request
 DLGLOBAL INFO UL_TBF{FINISHED}: Deallocated
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
 DLGLOBAL INFO DL_TBF_ASS{IDLE}: Deallocated
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-CCCH_DATA.indication
+DLGLOBAL DEBUG Rx SI13 from lower layers
 DLGLOBAL INFO Rx from upper layers: GRR-UNITDATA.request
 DLGLOBAL INFO TLLI=0x00002342 not found, creating entity on the fly
 DLGLOBAL INFO DL_TBF_ASS{IDLE}: Allocated
@@ -634,14 +640,123 @@ DLGLOBAL INFO UL_TBF{ASSIGN}: state_chg to FLOW
 DLGLOBAL INFO UL_TBF_ASS{COMPLETED}: state_chg to IDLE
 DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=200)
+DLGLOBAL DEBUG -- Chunk with length 200 larger than space (26) left in block: copy only remaining space, and we are done
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=15): 00 00 23 42 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=15)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 3c 01 01 00 00 23 42 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 
+DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
+DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
+DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent (1 phase access), start T3166
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) N3104 inc (1)
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_DATA.indication
+DLGLOBAL INFO TS=7 FN=4 Rx Pkt UL ACK/NACK
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Got GPRS UL ACK bitmap: SSN: 1, BSN 0 to 1 - 1 (1 blocks), "R"
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) ack:  (BSN=0)"R"(BSN=0)  R=ACK I=NACK
+DLGLOBAL DEBUG - got ack for BSN=0
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) V(B): (V(A)=1)""(V(S)-1=0)  A=Acked N=Nacked U=Unacked X=Resend-Unacked I=Invalid
+DLGLOBAL INFO UL_TBF{FLOW}: Received Event RX_UL_ACK_NACK
+DLGLOBAL INFO UL_TBF{FLOW}: Contention resolution succeeded, stop T3166
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 1, CS=CS-2
+DLGLOBAL DEBUG -- Chunk with length 174 larger than space (30) left in block: copy only remaining space, and we are done
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=1, CS-2, CV=15): ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 1 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=1 CV=15)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 1, CS-2): 3c 00 03 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 2, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Entering Countdown procedure CV=4
+DLGLOBAL DEBUG -- Chunk with length 144 larger than space (30) left in block: copy only remaining space, and we are done
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=2, CS-2, CV=4): ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 2 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=2 CV=4)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 2, CS-2): 10 00 05 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 3, CS=CS-2
+DLGLOBAL DEBUG -- Chunk with length 114 larger than space (30) left in block: copy only remaining space, and we are done
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=3, CS-2, CV=3): ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 3 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=3 CV=3)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 3, CS-2): 0c 00 07 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 4, CS=CS-2
+DLGLOBAL DEBUG -- Chunk with length 84 larger than space (30) left in block: copy only remaining space, and we are done
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=4, CS-2, CV=2): ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 4 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=4 CV=2)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 4, CS-2): 08 00 09 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 5, CS=CS-2
+DLGLOBAL DEBUG -- Chunk with length 54 larger than space (30) left in block: copy only remaining space, and we are done
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=5, CS-2, CV=1): ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 5 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=5 CV=1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 5, CS-2): 04 00 0b ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 6, CS=CS-2
+DLGLOBAL DEBUG -- Chunk with length 24 is less than remaining space (30): add length header to delimit LLC frame
+DLGLOBAL DEBUG -- Final block, so we done.
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Complete UL frame, len=0
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=6, CS-2, CV=0): 61 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 6 BSN2 -1)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=6 CV=0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 6, CS-2): 00 00 0c 61 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 2b 2b 2b 2b 2b 00 
+DLGLOBAL INFO UL_TBF{FLOW}: Received Event LAST_UL_DATA_SENT
+DLGLOBAL INFO UL_TBF{FLOW}: Last UL block sent (CV=0), start T3182
+DLGLOBAL INFO UL_TBF{FLOW}: state_chg to FINISHED
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
+DLGLOBAL INFO DL_TBF_ASS{IDLE}: Deallocated
+DLGLOBAL INFO UL_TBF_ASS{IDLE}: Deallocated
+DLGLOBAL INFO UL_TBF{FINISHED}: Send L1CTL-CFG_UL_TBF.req ul_tbf_nr=0 (release)
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-CFG_UL_TBF.request
+DLGLOBAL INFO UL_TBF{FINISHED}: Deallocated
+DLGLOBAL INFO Rx from upper layers: GRR-UNITDATA.request
+DLGLOBAL INFO TLLI=0x00002342 not found, creating entity on the fly
+DLGLOBAL INFO DL_TBF_ASS{IDLE}: Allocated
+DLGLOBAL INFO UL_TBF{NEW}: Allocated
+DLGLOBAL INFO UL_TBF_ASS{IDLE}: Allocated
+DLGLOBAL INFO UL_TBF_ASS{IDLE}: Received Event START
+DLGLOBAL INFO UL_TBF{NEW}: Received Event UL_ASS_START
+DLGLOBAL INFO UL_TBF{NEW}: state_chg to ASSIGN
+DLGLOBAL INFO UL_TBF_ASS{IDLE}: Send RACH.req ra=0x7e
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-RACH.request
+DLGLOBAL INFO UL_TBF_ASS{IDLE}: state_chg to WAIT_CCCH_IMM_ASS
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-CCCH_DATA.indication
+DLGLOBAL INFO UL_TBF_ASS{WAIT_CCCH_IMM_ASS}: Received Event RX_CCCH_IMM_ASS
+DLGLOBAL INFO UL_TBF_ASS{WAIT_CCCH_IMM_ASS}: ImmAss TFI=0 initCS=CS-2 startTimeFN=0
+DLGLOBAL INFO UL_TBF_ASS{WAIT_CCCH_IMM_ASS}: ImmAss DynamicAlloc (1phase access) ts_nr=7 usf=0
+DLGLOBAL INFO UL_TBF_ASS{WAIT_CCCH_IMM_ASS}: state_chg to COMPLETED
+DLGLOBAL INFO UL_TBF{ASSIGN}: Received Event UL_ASS_COMPL
+DLGLOBAL INFO UL_TBF{ASSIGN}: Send L1CTL-CFG_UL_TBF.req ul_tbf_nr=0 ul_slotmask=0x80
+DLGLOBAL DEBUG Tx to lower layers: L1CTL-CFG_UL_TBF.request
+DLGLOBAL INFO UL_TBF{ASSIGN}: state_chg to FLOW
+DLGLOBAL INFO UL_TBF_ASS{COMPLETED}: state_chg to IDLE
+DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Sending new block at BSN 0, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Entering Countdown procedure CV=0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Dequeue next LLC (len=14)
 DLGLOBAL DEBUG -- Chunk with length 14 is less than remaining space (26): add length header to delimit LLC frame
 DLGLOBAL DEBUG -- Final block, so we done.
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Complete UL frame, len=0
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN 0, CS-2): 39 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) data block (BSN=0, CS-2, CV=0): 39 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) Copying data unit 0 (BSN=0 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00002342) msg block (BSN 0, CS-2): 00 01 00 39 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
@@ -775,14 +890,15 @@ DLGLOBAL DEBUG GRE(00000001) Tx Packet Control Ack
 DLGLOBAL DEBUG Tx to lower layers: L1CTL-PDCH_DATA.request
 DLGLOBAL DEBUG Rx from lower layers: L1CTL-PDCH_RTS.indication
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Sending new block at BSN 0, CS=CS-2
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Entering Countdown procedure CV=0
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Dequeue next LLC (len=14)
 DLGLOBAL DEBUG -- Chunk with length 14 is less than remaining space (30): add length header to delimit LLC frame
 DLGLOBAL DEBUG -- Final block, so we done.
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Complete UL frame, len=0
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) data block (BSN 0, CS-2): 39 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) data block (BSN=0, CS-2, CV=0): 39 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) need_padding 0 spb_status 0 spb 0 (BSN1 0 BSN2 -1)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Copying 1 RLC blocks, 1 BSNs
-DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Copying data unit 0 (BSN 0)
+DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) Copying data unit 0 (BSN=0 CV=0)
 DLGLOBAL DEBUG TBF(UL:NR-0:TLLI-00000001) msg block (BSN 0, CS-2): 00 06 00 39 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 
 DLGLOBAL INFO UL_TBF{FLOW}: Received Event FIRST_UL_DATA_SENT
 DLGLOBAL INFO UL_TBF{FLOW}: First UL block sent, stop T3164
diff --git a/tests/rlcmac/rlcmac_prim_test.ok b/tests/rlcmac/rlcmac_prim_test.ok
index 100749a..b555cbe 100644
--- a/tests/rlcmac/rlcmac_prim_test.ok
+++ b/tests/rlcmac/rlcmac_prim_test.ok
@@ -115,11 +115,31 @@ RTS 3: FN=26
 test_rlcmac_prim_down_cb(): Rx L1CTL-CFG_UL_TBF.request ul_tbf_nr=0 ul_slotmask=0x00
 test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=26 ts=7 data_len=34 data=[00 00 02 1d 11 e5 10 00 e2 18 f2 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 ]
 === test_ul_tbf_last_data_cv0_retrans_max end ===
-=== test_ul_tbf_request_another_ul_tbf start ===
+=== test_ul_tbf_countdown_procedure start ===
 sys={0.000000}, mono={0.000000}: clock_override_set
 test_rlcmac_prim_down_cb(): Rx L1CTL-RACH.request ra=0x7b
 test_rlcmac_prim_down_cb(): Rx L1CTL-CFG_UL_TBF.request ul_tbf_nr=0 ul_slotmask=0x80
 test_rlcmac_prim_up_cb(): Rx GMMRR-LLC_TRANSMITTED.indication TLLI=0x00002342
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=4 ts=7 data_len=34 data=[3c 01 01 00 00 23 42 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 ]
+RTS 0: FN=8
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=8 ts=7 data_len=34 data=[3c 00 03 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 ]
+RTS 1: FN=13
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=13 ts=7 data_len=34 data=[10 00 05 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 ]
+RTS 2: FN=17
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=17 ts=7 data_len=34 data=[0c 00 07 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 ]
+RTS 3: FN=21
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=21 ts=7 data_len=34 data=[08 00 09 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 ]
+RTS 4: FN=26
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=26 ts=7 data_len=34 data=[04 00 0b ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 00 ]
+RTS 5: FN=30
+test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=30 ts=7 data_len=34 data=[00 00 0c 61 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab 2b 2b 2b 2b 2b 00 ]
+=== test_ul_tbf_countdown_procedure end ===
+test_rlcmac_prim_down_cb(): Rx L1CTL-CFG_UL_TBF.request ul_tbf_nr=0 ul_slotmask=0x00
+=== test_ul_tbf_request_another_ul_tbf start ===
+sys={0.000000}, mono={0.000000}: clock_override_set
+test_rlcmac_prim_down_cb(): Rx L1CTL-RACH.request ra=0x7e
+test_rlcmac_prim_down_cb(): Rx L1CTL-CFG_UL_TBF.request ul_tbf_nr=0 ul_slotmask=0x80
+test_rlcmac_prim_up_cb(): Rx GMMRR-LLC_TRANSMITTED.indication TLLI=0x00002342
 test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=4 ts=7 data_len=34 data=[00 01 00 39 00 00 23 42 01 c0 00 08 01 01 d5 71 00 00 08 29 26 24 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 00 ]
 test_rlcmac_prim_down_cb(): Rx L1CTL-CFG_UL_TBF.request ul_tbf_nr=0 ul_slotmask=0x00
 test_rlcmac_prim_down_cb(): Rx L1CTL-PDCH_DATA.request fn=17 ts=7 data_len=23 data=[40 16 40 00 08 d0 a0 bc 00 00 00 00 00 00 70 00 38 00 00 2b 2b 2b 2b ]