diff --git a/src/osmo-bts-litecell15/lc15_l1_if.c b/src/osmo-bts-litecell15/lc15_l1_if.c
index 043a3ba..dce9e53 100644
--- a/src/osmo-bts-litecell15/lc15_l1_if.c
+++ b/src/osmo-bts-litecell15/lc15_l1_if.c
@@ -367,7 +367,7 @@
 	return 0;
 }
 
-void *l1if_open_pdch(uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
+void *l1if_open_pdch(uint8_t bts_nr, uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
 {
 	struct lc15l1_hdl *fl1h;
 	int rc;
diff --git a/src/osmo-bts-oc2g/oc2g_l1_if.c b/src/osmo-bts-oc2g/oc2g_l1_if.c
index c827d72..93b4654 100644
--- a/src/osmo-bts-oc2g/oc2g_l1_if.c
+++ b/src/osmo-bts-oc2g/oc2g_l1_if.c
@@ -372,7 +372,7 @@
 	return 0;
 }
 
-void *l1if_open_pdch(uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
+void *l1if_open_pdch(uint8_t bts_nr, uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
 {
 	struct oc2gl1_hdl *fl1h;
 	int rc;
diff --git a/src/osmo-bts-sysmo/sysmo_l1_if.c b/src/osmo-bts-sysmo/sysmo_l1_if.c
index 348497f..99ccf9a 100644
--- a/src/osmo-bts-sysmo/sysmo_l1_if.c
+++ b/src/osmo-bts-sysmo/sysmo_l1_if.c
@@ -352,7 +352,7 @@
 	return 0;
 }
 
-void *l1if_open_pdch(uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
+void *l1if_open_pdch(uint8_t bts_nr, uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
 {
 	struct femtol1_hdl *fl1h;
 	int rc;
diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp
index 3eff68f..6c4ed22 100644
--- a/src/pcu_l1_if.cpp
+++ b/src/pcu_l1_if.cpp
@@ -731,6 +731,9 @@
 	unsigned int trx_nr, ts_nr;
 	unsigned int i;
 
+	if (llist_count(&the_pcu->bts_list) > 1)
+		LOGP(DL1IF, LOGL_ERROR, "more than one BTS regsitered at this PCU. This PCU has only been tested with one BTS! OS#5930\n");
+
 	if (info_ind->version != PCU_IF_VERSION) {
 		fprintf(stderr, "PCU interface version number of BTS (%u) is "
 			"different (%u).\nPlease re-compile!\n",
@@ -864,7 +867,7 @@
 				info_ind->trx[trx_nr].hlayer1);
 				if (!bts->trx[trx_nr].fl1h)
 					bts->trx[trx_nr].fl1h = l1if_open_pdch(
-						trx_nr,
+						bts->nr, trx_nr,
 						info_ind->trx[trx_nr].hlayer1,
 						the_pcu->gsmtap);
 			if (!bts->trx[trx_nr].fl1h) {
diff --git a/src/pcu_l1_if_phy.h b/src/pcu_l1_if_phy.h
index 297883b..7eba5cc 100644
--- a/src/pcu_l1_if_phy.h
+++ b/src/pcu_l1_if_phy.h
@@ -4,7 +4,7 @@
 #include <osmocom/core/gsmtap_util.h>
 
 int l1if_init(void);
-void *l1if_open_pdch(uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap);
+void *l1if_open_pdch(uint8_t bts_nr, uint8_t trx_no, uint32_t hlayer1, struct gsmtap_inst *gsmtap);
 int l1if_connect_pdch(void *obj, uint8_t ts);
 int l1if_pdch_req(void *obj, uint8_t ts, int is_ptcch, uint32_t fn, uint16_t arfcn, uint8_t block_nr, uint8_t *data,
 		  uint8_t len);