diff --git a/src/host/layer23/include/osmocom/bb/common/ms.h b/src/host/layer23/include/osmocom/bb/common/ms.h
index 0b3e13cce..36d3e3bae 100644
--- a/src/host/layer23/include/osmocom/bb/common/ms.h
+++ b/src/host/layer23/include/osmocom/bb/common/ms.h
@@ -42,6 +42,7 @@ struct osmosap_entity {
 
 struct osmol1_entity {
 	int (*l1_traffic_ind)(struct osmocom_ms *ms, struct msgb *msg);
+	int (*l1_gprs_ul_block_cnf)(struct osmocom_ms *ms, struct msgb *msg);
 	int (*l1_gprs_dl_block_ind)(struct osmocom_ms *ms, struct msgb *msg);
 	int (*l1_gprs_rts_ind)(struct osmocom_ms *ms, struct msgb *msg);
 };
diff --git a/src/host/layer23/include/osmocom/bb/modem/grr.h b/src/host/layer23/include/osmocom/bb/modem/grr.h
index 99800ad3e..a86a089b9 100644
--- a/src/host/layer23/include/osmocom/bb/modem/grr.h
+++ b/src/host/layer23/include/osmocom/bb/modem/grr.h
@@ -25,6 +25,7 @@ enum grr_fsm_event {
 	GRR_EV_PDCH_UL_TBF_CFG_REQ,
 	GRR_EV_PDCH_DL_TBF_CFG_REQ,
 	GRR_EV_PDCH_BLOCK_REQ,
+	GRR_EV_PDCH_BLOCK_CNF,
 	GRR_EV_PDCH_BLOCK_IND,
 	GRR_EV_PDCH_RTS_IND,
 };
diff --git a/src/host/layer23/src/common/l1ctl.c b/src/host/layer23/src/common/l1ctl.c
index a0f25b8d0..949791030 100644
--- a/src/host/layer23/src/common/l1ctl.c
+++ b/src/host/layer23/src/common/l1ctl.c
@@ -949,6 +949,36 @@ static int rx_l1_neigh_pm_ind(struct osmocom_ms *ms, struct msgb *msg)
 	return 0;
 }
 
+/* Receive L1CTL_GPRS_UL_BLOCK_CNF */
+static int rx_l1_gprs_ul_block_cnf(struct osmocom_ms *ms, struct msgb *msg)
+{
+	const struct l1ctl_gprs_ul_block_cnf *cnf = (void *)msg->l1h;
+
+	if (msgb_l1len(msg) < sizeof(*cnf)) {
+		LOGP(DL1C, LOGL_ERROR,
+		     "Rx malformed GPRS UL BLOCK.cnf (len=%u < %zu)\n",
+		     msgb_l1len(msg), sizeof(*cnf));
+		return -EINVAL;
+	}
+	if (OSMO_UNLIKELY(cnf->tn >= 8)) {
+		LOGP(DL1C, LOGL_ERROR,
+		     "Rx malformed GPRS UL BLOCK.cnf (tn=%u)\n", cnf->tn);
+		return -EINVAL;
+	}
+
+	msg->l2h = (void *)&cnf->data[0];
+
+	DEBUGP(DL1C, "Rx GPRS UL BLOCK.cnf (fn=%u, tn=%u, len=%u): %s\n",
+	       ntohl(cnf->fn), cnf->tn, msgb_l2len(msg), msgb_hexdump_l2(msg));
+
+	/* distribute or drop */
+	if (ms->l1_entity.l1_gprs_ul_block_cnf)
+		return ms->l1_entity.l1_gprs_ul_block_cnf(ms, msg);
+
+	msgb_free(msg);
+	return 0;
+}
+
 /* Receive L1CTL_GPRS_DL_BLOCK_IND */
 static int rx_l1_gprs_dl_block_ind(struct osmocom_ms *ms, struct msgb *msg)
 {
@@ -1171,6 +1201,9 @@ int l1ctl_recv(struct osmocom_ms *ms, struct msgb *msg)
 	case L1CTL_TRAFFIC_CONF:
 		msgb_free(msg);
 		break;
+	case L1CTL_GPRS_UL_BLOCK_CNF:
+		rc = rx_l1_gprs_ul_block_cnf(ms, msg);
+		break;
 	case L1CTL_GPRS_DL_BLOCK_IND:
 		rc = rx_l1_gprs_dl_block_ind(ms, msg);
 		break;
diff --git a/src/host/layer23/src/modem/grr.c b/src/host/layer23/src/modem/grr.c
index cbabdc9a0..cd325c4c6 100644
--- a/src/host/layer23/src/modem/grr.c
+++ b/src/host/layer23/src/modem/grr.c
@@ -521,6 +521,18 @@ static void handle_pdch_establish_req(struct osmo_fsm_inst *fi,
 	osmo_fsm_inst_state_chg(fi, GRR_ST_PACKET_TRANSFER, 0, 0);
 }
 
+static void handle_pdch_block_cnf(struct osmocom_ms *ms, struct msgb *msg)
+{
+	const struct l1ctl_gprs_ul_block_cnf *cnf = (void *)msg->l1h;
+	const uint32_t fn = osmo_load32be(&cnf->fn);
+	struct osmo_gprs_rlcmac_prim *prim;
+
+	prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_pdch_data_cnf(cnf->tn, fn,
+							       msgb_l2(msg),
+							       msgb_l2len(msg));
+	osmo_gprs_rlcmac_prim_lower_up(prim);
+}
+
 static void handle_pdch_block_ind(struct osmocom_ms *ms, struct msgb *msg)
 {
 	const struct l1ctl_gprs_dl_block_ind *ind = (void *)msg->l1h;
@@ -753,6 +765,9 @@ static void grr_st_packet_transfer_action(struct osmo_fsm_inst *fi,
 					   lp->pdch_data_req.data_len);
 		break;
 	}
+	case GRR_EV_PDCH_BLOCK_CNF:
+		handle_pdch_block_cnf(ms, (struct msgb *)data);
+		break;
 	case GRR_EV_PDCH_BLOCK_IND:
 		handle_pdch_block_ind(ms, (struct msgb *)data);
 		break;
@@ -819,6 +834,7 @@ static const struct osmo_fsm_state grr_fsm_states[] = {
 		.in_event_mask  = S(GRR_EV_PDCH_UL_TBF_CFG_REQ)
 				| S(GRR_EV_PDCH_DL_TBF_CFG_REQ)
 				| S(GRR_EV_PDCH_BLOCK_REQ)
+				| S(GRR_EV_PDCH_BLOCK_CNF)
 				| S(GRR_EV_PDCH_BLOCK_IND)
 				| S(GRR_EV_PDCH_RTS_IND)
 				| S(GRR_EV_PDCH_RELEASE_REQ),
@@ -838,6 +854,7 @@ static const struct value_string grr_fsm_event_names[] = {
 	OSMO_VALUE_STRING(GRR_EV_PDCH_UL_TBF_CFG_REQ),
 	OSMO_VALUE_STRING(GRR_EV_PDCH_DL_TBF_CFG_REQ),
 	OSMO_VALUE_STRING(GRR_EV_PDCH_BLOCK_REQ),
+	OSMO_VALUE_STRING(GRR_EV_PDCH_BLOCK_CNF),
 	OSMO_VALUE_STRING(GRR_EV_PDCH_BLOCK_IND),
 	OSMO_VALUE_STRING(GRR_EV_PDCH_RTS_IND),
 	{ 0, NULL }
diff --git a/src/host/layer23/src/modem/rlcmac.c b/src/host/layer23/src/modem/rlcmac.c
index a9588f7aa..7f7b5661d 100644
--- a/src/host/layer23/src/modem/rlcmac.c
+++ b/src/host/layer23/src/modem/rlcmac.c
@@ -162,12 +162,17 @@ static int modem_rlcmac_prim_down_cb(struct osmo_gprs_rlcmac_prim *prim, void *u
 	}
 }
 
-static int l1ctl_dl_block_cb(struct osmocom_ms *ms, struct msgb *msg)
+static int l1ctl_ul_block_cnf_cb(struct osmocom_ms *ms, struct msgb *msg)
+{
+	return osmo_fsm_inst_dispatch(ms->grr_fi, GRR_EV_PDCH_BLOCK_CNF, msg);
+}
+
+static int l1ctl_dl_block_ind_cb(struct osmocom_ms *ms, struct msgb *msg)
 {
 	return osmo_fsm_inst_dispatch(ms->grr_fi, GRR_EV_PDCH_BLOCK_IND, msg);
 }
 
-static int l1ctl_rts_cb(struct osmocom_ms *ms, struct msgb *msg)
+static int l1ctl_rts_ind_cb(struct osmocom_ms *ms, struct msgb *msg)
 {
 	return osmo_fsm_inst_dispatch(ms->grr_fi, GRR_EV_PDCH_RTS_IND, msg);
 }
@@ -186,8 +191,9 @@ int modem_rlcmac_init(struct osmocom_ms *ms)
 	osmo_gprs_rlcmac_prim_set_up_cb(modem_rlcmac_prim_up_cb, ms);
 	osmo_gprs_rlcmac_prim_set_down_cb(modem_rlcmac_prim_down_cb, ms);
 
-	ms->l1_entity.l1_gprs_dl_block_ind = &l1ctl_dl_block_cb;
-	ms->l1_entity.l1_gprs_rts_ind = &l1ctl_rts_cb;
+	ms->l1_entity.l1_gprs_ul_block_cnf = &l1ctl_ul_block_cnf_cb;
+	ms->l1_entity.l1_gprs_dl_block_ind = &l1ctl_dl_block_ind_cb;
+	ms->l1_entity.l1_gprs_rts_ind = &l1ctl_rts_ind_cb;
 
 	return rc;
 }