diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index cb64c4cfb..52b20a8b9 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -447,6 +447,8 @@ struct gsm_abis_mo {
 	bool get_attr_rep_received;
 	bool set_attr_sent;
 	bool set_attr_ack_received;
+	bool rsl_connect_sent;
+	bool rsl_connect_ack_received;
 	bool force_rf_lock;
 };
 
diff --git a/include/osmocom/bsc/nm_common_fsm.h b/include/osmocom/bsc/nm_common_fsm.h
index 1d56220be..b41d24a60 100644
--- a/include/osmocom/bsc/nm_common_fsm.h
+++ b/include/osmocom/bsc/nm_common_fsm.h
@@ -40,6 +40,8 @@ enum nm_fsm_events {
 	NM_EV_OML_DOWN,
 	NM_EV_FORCE_LOCK, /* Only supported by RadioCarrier so far */
 	NM_EV_FEATURE_NEGOTIATED, /* Sent by BTS to NSVC MO */
+	NM_EV_RSL_CONNECT_ACK, /* Sent by BTS to BBTRANSC MO */
+	NM_EV_RSL_CONNECT_NACK, /* Sent by BTS to BBTRANSC MO */
 };
 extern const struct value_string nm_fsm_event_names[];
 
diff --git a/src/osmo-bsc/abis_nm.c b/src/osmo-bsc/abis_nm.c
index b151f36e6..938f45d13 100644
--- a/src/osmo-bsc/abis_nm.c
+++ b/src/osmo-bsc/abis_nm.c
@@ -2966,6 +2966,7 @@ static int abis_nm_rx_ipacc(struct msgb *msg)
 		signal.foh = foh;
 		osmo_signal_dispatch(SS_NM, S_NM_IPACC_NACK, &signal);
 		break;
+	case NM_MT_IPACC_RSL_CONNECT_ACK:
 	case NM_MT_IPACC_SET_NVATTR_ACK:
 	case NM_MT_IPACC_SET_ATTR_ACK:
 		signal.bts = bts;
diff --git a/src/osmo-bsc/bts_ipaccess_nanobts.c b/src/osmo-bsc/bts_ipaccess_nanobts.c
index 0af5a2874..316594465 100644
--- a/src/osmo-bsc/bts_ipaccess_nanobts.c
+++ b/src/osmo-bsc/bts_ipaccess_nanobts.c
@@ -443,12 +443,56 @@ static void nm_rx_ipacc_set_attr_ack(struct ipacc_ack_signal_data *sig_data)
 	}
 }
 
+static void nm_rx_ipacc_rsl_connect_ack(struct ipacc_ack_signal_data *sig_data)
+{
+	struct gsm_bts *bts = sig_data->bts;
+	struct abis_om_fom_hdr *foh = sig_data->foh;
+	struct gsm_bts_trx *trx;
+
+	if (foh->obj_class != NM_OC_BASEB_TRANSC) {
+		LOGPFOH(DNM, LOGL_ERROR, foh, "IPACC RSL Connect ACK received on incorrect object class %d!\n", foh->obj_class);
+		return;
+	}
+
+	trx = gsm_bts_trx_num(bts, foh->obj_inst.trx_nr);
+	osmo_fsm_inst_dispatch(trx->bb_transc.mo.fi, NM_EV_RSL_CONNECT_ACK, NULL);
+}
+
 static void nm_rx_ipacc_ack(struct ipacc_ack_signal_data *sig_data)
 {
 	switch (sig_data->foh->msg_type) {
 	case NM_MT_IPACC_SET_ATTR_ACK:
 		nm_rx_ipacc_set_attr_ack(sig_data);
 		break;
+	case NM_MT_IPACC_RSL_CONNECT_ACK:
+		nm_rx_ipacc_rsl_connect_ack(sig_data);
+		break;
+	default:
+		break;
+	}
+}
+
+static void nm_rx_ipacc_rsl_connect_nack(struct ipacc_ack_signal_data *sig_data)
+{
+	struct gsm_bts *bts = sig_data->bts;
+	struct abis_om_fom_hdr *foh = sig_data->foh;
+	struct gsm_bts_trx *trx;
+
+	if (foh->obj_class != NM_OC_BASEB_TRANSC) {
+		LOGPFOH(DNM, LOGL_ERROR, foh, "IPACC RSL Connect NACK received on incorrect object class %d!\n", foh->obj_class);
+		return;
+	}
+
+	trx = gsm_bts_trx_num(bts, foh->obj_inst.trx_nr);
+	osmo_fsm_inst_dispatch(trx->bb_transc.mo.fi, NM_EV_RSL_CONNECT_NACK, NULL);
+}
+
+static void nm_rx_ipacc_nack(struct ipacc_ack_signal_data *sig_data)
+{
+	switch (sig_data->foh->msg_type) {
+	case NM_MT_IPACC_RSL_CONNECT_ACK:
+		nm_rx_ipacc_rsl_connect_nack(sig_data);
+		break;
 	default:
 		break;
 	}
@@ -487,6 +531,9 @@ static int bts_ipa_nm_sig_cb(unsigned int subsys, unsigned int signal,
 	case S_NM_IPACC_ACK:
 		nm_rx_ipacc_ack(signal_data);
 		return 0;
+	case S_NM_IPACC_NACK:
+		nm_rx_ipacc_nack(signal_data);
+		return 0;
 	default:
 		break;
 	}
diff --git a/src/osmo-bsc/nm_bb_transc_fsm.c b/src/osmo-bsc/nm_bb_transc_fsm.c
index bf2469145..3a8786bfe 100644
--- a/src/osmo-bsc/nm_bb_transc_fsm.c
+++ b/src/osmo-bsc/nm_bb_transc_fsm.c
@@ -32,6 +32,7 @@
 #include <osmocom/bsc/signal.h>
 #include <osmocom/bsc/abis_nm.h>
 #include <osmocom/bsc/bts_ipaccess_nanobts_omlattr.h>
+#include <osmocom/bsc/ipaccess.h>
 #include <osmocom/bsc/nm_common_fsm.h>
 #include <osmocom/bsc/debug.h>
 
@@ -63,6 +64,8 @@ static void st_op_disabled_notinstalled_on_enter(struct osmo_fsm_inst *fi, uint3
 	bb_transc->mo.get_attr_sent = false;
 	bb_transc->mo.get_attr_rep_received = false;
 	bb_transc->mo.adm_unlock_sent = false;
+	bb_transc->mo.rsl_connect_sent = false;
+	bb_transc->mo.rsl_connect_ack_received = false;
 	bb_transc->mo.opstart_sent = false;
 }
 
@@ -125,14 +128,22 @@ static void configure_loop(struct gsm_bts_bb_trx *bb_transc, const struct gsm_nm
 				      NM_STATE_UNLOCKED);
 	}
 
+	/* Provision BTS with RSL IP addr & port to connect to: */
 	if (allow_opstart && state->administrative == NM_STATE_UNLOCKED &&
-	    !bb_transc->mo.opstart_sent) {
-		bb_transc->mo.opstart_sent = true;
-		abis_nm_opstart(trx->bts, NM_OC_BASEB_TRANSC, trx->bts->bts_nr, trx->nr, 0xff);
-		/* TRX software is active, tell it to initiate RSL Link */
+	    !bb_transc->mo.rsl_connect_sent && !bb_transc->mo.rsl_connect_ack_received) {
+		bb_transc->mo.rsl_connect_sent = true;
 		abis_nm_ipaccess_rsl_connect(trx, trx->bts->ip_access.rsl_ip,
 					     3003, trx->rsl_tei_primary);
 	}
+
+	/* OPSTART after receiving RSL CONNECT ACK. We cannot delay until the
+	 * RSL/IPA socket is connected to us because nanoBTS only attempts
+	 * connection after receiving an OPSTART: */
+	if (allow_opstart && state->administrative == NM_STATE_UNLOCKED &&
+	    bb_transc->mo.rsl_connect_ack_received && !bb_transc->mo.opstart_sent) {
+		bb_transc->mo.opstart_sent = true;
+		abis_nm_opstart(trx->bts, NM_OC_BASEB_TRANSC, trx->bts->bts_nr, trx->nr, 0xff);
+	}
 }
 
 static void st_op_disabled_dependency_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
@@ -150,6 +161,7 @@ static void st_op_disabled_dependency_on_enter(struct osmo_fsm_inst *fi, uint32_
 static void st_op_disabled_dependency(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	struct gsm_bts_bb_trx *bb_transc = (struct gsm_bts_bb_trx *)fi->priv;
+	struct gsm_bts_trx *trx = gsm_bts_bb_trx_get_trx(bb_transc);
 	struct nm_statechg_signal_data *nsd;
 	const struct gsm_nm_state *new_state;
 
@@ -159,6 +171,14 @@ static void st_op_disabled_dependency(struct osmo_fsm_inst *fi, uint32_t event,
 		bb_transc->mo.get_attr_sent = false;
 		configure_loop(bb_transc, &bb_transc->mo.nm_state, false);
 		return;
+	case NM_EV_RSL_CONNECT_ACK:
+		bb_transc->mo.rsl_connect_ack_received = true;
+		bb_transc->mo.rsl_connect_sent = false;
+		configure_loop(bb_transc, &bb_transc->mo.nm_state, false);
+		break;
+	case NM_EV_RSL_CONNECT_NACK:
+		ipaccess_drop_oml_deferred(trx->bts);
+		break;
 	case NM_EV_STATE_CHG_REP:
 		nsd = (struct nm_statechg_signal_data *)data;
 		new_state = &nsd->new_state;
@@ -207,6 +227,14 @@ static void st_op_disabled_offline(struct osmo_fsm_inst *fi, uint32_t event, voi
 		bb_transc->mo.get_attr_sent = false;
 		configure_loop(bb_transc, &bb_transc->mo.nm_state, true);
 		return;
+	case NM_EV_RSL_CONNECT_ACK:
+		bb_transc->mo.rsl_connect_ack_received = true;
+		bb_transc->mo.rsl_connect_sent = false;
+		configure_loop(bb_transc, &bb_transc->mo.nm_state, true);
+		break;
+	case NM_EV_RSL_CONNECT_NACK:
+		ipaccess_drop_oml_deferred(trx->bts);
+		break;
 	case NM_EV_STATE_CHG_REP:
 		nsd = (struct nm_statechg_signal_data *)data;
 		new_state = &nsd->new_state;
@@ -251,8 +279,10 @@ static void st_op_enabled_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state
 	  reused as soon as we move back to Disabled */
 	bb_transc->mo.get_attr_sent = false;
 	bb_transc->mo.get_attr_rep_received = false;
-	bb_transc->mo.opstart_sent = false;
 	bb_transc->mo.adm_unlock_sent = false;
+	bb_transc->mo.rsl_connect_ack_received = false;
+	bb_transc->mo.rsl_connect_sent = false;
+	bb_transc->mo.opstart_sent = false;
 
 	nm_bb_transc_fsm_becomes_enabled(bb_transc);
 }
@@ -330,7 +360,9 @@ static struct osmo_fsm_state nm_bb_transc_fsm_states[] = {
 	[NM_BB_TRANSC_ST_OP_DISABLED_DEPENDENCY] = {
 		.in_event_mask =
 			X(NM_EV_STATE_CHG_REP) |
-			X(NM_EV_GET_ATTR_REP),
+			X(NM_EV_GET_ATTR_REP) |
+			X(NM_EV_RSL_CONNECT_ACK) |
+			X(NM_EV_RSL_CONNECT_NACK),
 		.out_state_mask =
 			X(NM_BB_TRANSC_ST_OP_DISABLED_NOTINSTALLED) |
 			X(NM_BB_TRANSC_ST_OP_DISABLED_OFFLINE) |
@@ -342,7 +374,9 @@ static struct osmo_fsm_state nm_bb_transc_fsm_states[] = {
 	[NM_BB_TRANSC_ST_OP_DISABLED_OFFLINE] = {
 		.in_event_mask =
 			X(NM_EV_STATE_CHG_REP) |
-			X(NM_EV_GET_ATTR_REP),
+			X(NM_EV_GET_ATTR_REP) |
+			X(NM_EV_RSL_CONNECT_ACK) |
+			X(NM_EV_RSL_CONNECT_NACK),
 		.out_state_mask =
 			X(NM_BB_TRANSC_ST_OP_DISABLED_NOTINSTALLED) |
 			X(NM_BB_TRANSC_ST_OP_DISABLED_DEPENDENCY) |
diff --git a/src/osmo-bsc/nm_common_fsm.c b/src/osmo-bsc/nm_common_fsm.c
index b0902b171..2bf38ac31 100644
--- a/src/osmo-bsc/nm_common_fsm.c
+++ b/src/osmo-bsc/nm_common_fsm.c
@@ -33,6 +33,8 @@ const struct value_string nm_fsm_event_names[] = {
 	{ NM_EV_OML_DOWN, "OML_DOWN" },
 	{ NM_EV_FORCE_LOCK, "FORCE_LOCK_CHG" },
 	{ NM_EV_FEATURE_NEGOTIATED, "FEATURE_NEGOTIATED" },
+	{ NM_EV_RSL_CONNECT_ACK, "RSL_CONNECT_ACK" },
+	{ NM_EV_RSL_CONNECT_NACK, "RSL_CONNECT_NACK" },
 	{ 0, NULL }
 };