diff --git a/src/bts.cpp b/src/bts.cpp
index f77c5a2..df08cc6 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -1389,7 +1389,7 @@
 
 struct GprsMs *bts_ms_by_imsi(struct gprs_rlcmac_bts *bts, const char *imsi)
 {
-	return bts_ms_store(bts)->get_ms(0, 0, imsi);
+	return bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi);
 }
 
 const struct llist_head* bts_ms_list(struct gprs_rlcmac_bts *bts)
diff --git a/src/pcu_vty_functions.cpp b/src/pcu_vty_functions.cpp
index 1745eea..28ecebf 100644
--- a/src/pcu_vty_functions.cpp
+++ b/src/pcu_vty_functions.cpp
@@ -236,7 +236,7 @@
 int pcu_vty_show_ms_by_imsi(struct vty *vty, struct gprs_rlcmac_bts *bts,
 	const char *imsi)
 {
-	GprsMs *ms = bts_ms_store(bts)->get_ms(0, 0, imsi);
+	GprsMs *ms = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi);
 	if (!ms) {
 		vty_out(vty, "Unknown IMSI '%s'.%s", imsi, VTY_NEWLINE);
 		return CMD_WARNING;
diff --git a/src/tbf.cpp b/src/tbf.cpp
index d15cd3d..cb5d9f3 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -225,7 +225,7 @@
 	if (!ms_check_tlli(ms(), tlli)) {
 		GprsMs *old_ms;
 
-		old_ms = bts_ms_store(bts)->get_ms(tlli, 0, NULL);
+		old_ms = bts_ms_store(bts)->get_ms(tlli, GSM_RESERVED_TMSI, NULL);
 		if (old_ms)
 			ms_merge_and_clear_ms(ms(), old_ms);
 	}
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index 9c99cf6..67ac573 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -295,7 +295,7 @@
 	/* If we got MS by TLLI above let's see if we already have another MS
 	 * object identified by IMSI and merge them */
 	if (ms && !ms_imsi_is_valid(ms) && imsi) {
-		ms_old = bts_ms_store(bts)->get_ms(0, 0, imsi);
+		ms_old = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi);
 		if (ms_old && ms_old != ms) {
 			/* The TLLI has changed (RAU), so there are two MS
 			 * objects for the same MS */
diff --git a/tests/ms/MsTest.cpp b/tests/ms/MsTest.cpp
index 2ff2fc2..cbafee9 100644
--- a/tests/ms/MsTest.cpp
+++ b/tests/ms/MsTest.cpp
@@ -416,10 +416,10 @@
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(ms_tlli(ms) == tlli + 0);
 
-	ms_tmp = store.get_ms(0, 0, imsi1);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi1);
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(strcmp(ms_imsi(ms), imsi1) == 0);
-	ms_tmp = store.get_ms(0, 0, imsi2);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi2);
 	OSMO_ASSERT(ms_tmp == NULL);
 
 	ms = prepare_ms(&store, tlli + 1, GPRS_RLCMAC_UL_TBF);
@@ -432,10 +432,10 @@
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(ms_tlli(ms) == tlli + 1);
 
-	ms_tmp = store.get_ms(0, 0, imsi1);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi1);
 	OSMO_ASSERT(ms_tmp != NULL);
 	OSMO_ASSERT(ms_tmp != ms);
-	ms_tmp = store.get_ms(0, 0, imsi2);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi2);
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(strcmp(ms_imsi(ms), imsi2) == 0);
 
diff --git a/tests/tbf/TbfTest.cpp b/tests/tbf/TbfTest.cpp
index 116b234..c18fa77 100644
--- a/tests/tbf/TbfTest.cpp
+++ b/tests/tbf/TbfTest.cpp
@@ -450,7 +450,7 @@
 	dl_tbf[1]->update_ms(0xf1000002, GPRS_RLCMAC_DL_TBF);
 
 	ms_set_imsi(dl_tbf[0]->ms(), "001001000000001");
-	ms1 = bts_ms_store(bts)->get_ms(0, 0, "001001000000001");
+	ms1 = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, "001001000000001");
 	OSMO_ASSERT(ms1 != NULL);
 	ms2 = bts_ms_store(bts)->get_ms(0xf1000001);
 	OSMO_ASSERT(ms2 != NULL);
@@ -459,9 +459,9 @@
 
 	/* change the IMSI on TBF 0 */
 	ms_set_imsi(dl_tbf[0]->ms(), "001001000000002");
-	ms1 = bts_ms_store(bts)->get_ms(0, 0, "001001000000001");
+	ms1 = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, "001001000000001");
 	OSMO_ASSERT(ms1 == NULL);
-	ms1 = bts_ms_store(bts)->get_ms(0, 0, "001001000000002");
+	ms1 = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, "001001000000002");
 	OSMO_ASSERT(ms1 != NULL);
 	OSMO_ASSERT(strcmp(ms_imsi(ms2), "001001000000002") == 0);
 	OSMO_ASSERT(ms1 == ms2);
@@ -470,7 +470,7 @@
 	{
 		ms_ref(ms2);
 		ms_set_imsi(dl_tbf[1]->ms(), "001001000000002");
-		ms1 = bts_ms_store(bts)->get_ms(0, 0, "001001000000002");
+		ms1 = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, "001001000000002");
 		OSMO_ASSERT(ms1 != NULL);
 		OSMO_ASSERT(ms1 != ms2);
 		OSMO_ASSERT(strcmp(ms_imsi(ms1), "001001000000002") == 0);
@@ -482,7 +482,7 @@
 	OSMO_ASSERT(ms2 == NULL);
 
 	tbf_free(dl_tbf[1]);
-	ms1 = bts_ms_store(bts)->get_ms(0, 0, "001001000000002");
+	ms1 = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, "001001000000002");
 	OSMO_ASSERT(ms1 == NULL);
 
 	TALLOC_FREE(the_pcu);
@@ -565,7 +565,7 @@
 		delay_csec, buf, sizeof(buf));
 	OSMO_ASSERT(rc >= 0);
 
-	ms = bts_ms_store(bts)->get_ms(0, 0, imsi);
+	ms = bts_ms_store(bts)->get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi);
 	OSMO_ASSERT(ms != NULL);
 	OSMO_ASSERT(ms_dl_tbf(ms) != NULL);
 	ms_dl_tbf(ms)->set_ta(0);
@@ -1708,7 +1708,7 @@
 {
 	GprsMs *ms, *ms2;
 
-	ms = bts_ms_store(bts)->get_ms(tlli, 0, imsi);
+	ms = bts_ms_store(bts)->get_ms(tlli, GSM_RESERVED_TMSI, imsi);
 
 	dl_tbf_handle(bts, tlli, 0, imsi, 0, 0,
 		1000, data, data_size);