diff --git a/openbsc/src/abis_nm.c b/openbsc/src/abis_nm.c
index fc00ca8..bb7248b 100644
--- a/openbsc/src/abis_nm.c
+++ b/openbsc/src/abis_nm.c
@@ -671,7 +671,7 @@
 		nm_state = &bts->bs11.rack.nm_state;
 		break;
 	case NM_OC_BS11_ENVABTSE:
-		if (obj_inst->trx_nr > ARRAY_SIZE(bts->bs11.envabtse))
+		if (obj_inst->trx_nr >= ARRAY_SIZE(bts->bs11.envabtse))
 			return NULL;
 		nm_state = &bts->bs11.envabtse[obj_inst->trx_nr].nm_state;
 		break;
@@ -682,7 +682,7 @@
 		nm_state = &bts->gprs.cell.nm_state;
 		break;
 	case NM_OC_GPRS_NSVC:
-		if (obj_inst->trx_nr > ARRAY_SIZE(bts->gprs.nsvc))
+		if (obj_inst->trx_nr >= ARRAY_SIZE(bts->gprs.nsvc))
 			return NULL;
 		nm_state = &bts->gprs.nsvc[obj_inst->trx_nr].nm_state;
 		break;
@@ -738,7 +738,7 @@
 		obj = &bts->gprs.cell;
 		break;
 	case NM_OC_GPRS_NSVC:
-		if (obj_inst->trx_nr > ARRAY_SIZE(bts->gprs.nsvc))
+		if (obj_inst->trx_nr >= ARRAY_SIZE(bts->gprs.nsvc))
 			return NULL;
 		obj = &bts->gprs.nsvc[obj_inst->trx_nr];
 		break;