diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 587e14a..47f8a29 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -3534,7 +3534,6 @@
 		repeat;
 		}
 	[] L1CTL.receive(tr_L1CTL_DATA_IND(t_RslChanNr_PCH_AGCH(0), ?)) -> value l1_dl {
-		/* somehow dec_SystemInformation will try to decode even non-RR as SI */
 		var GsmRrMessage rr := dec_GsmRrMessage(l1_dl.payload.data_ind.payload);
 		if (not match(rr, tr_IMM_ASS(42, ?, 5, ?, ?))) {
 			/* FIXME: Why are we seeing paging requests on PCH/AGCH? */
@@ -3936,15 +3935,12 @@
 	T.start;
 	alt {
 	[] pt.receive(tr_L1CTL_DATA_IND(t_RslChanNr_BCCH(0), ?)) -> value l1_dl {
-		/* somehow dec_SystemInformation will try to decode even non-RR as SI */
-		if (not (l1_dl.payload.data_ind.payload[1] ==  '06'O)) {
-			log("Ignoring non-RR SI ", l1_dl);
+		var SystemInformationFn sig := { frame_number := l1_dl.dl_info.frame_nr };
+		if (dec_SystemInformationSafe(l1_dl.payload.data_ind.payload, sig.si) != 0) {
+			log("Ignoring non-RR or invalid SI ", l1_dl);
 			repeat;
 		}
-		var SystemInformationFn sig := {
-			frame_number := l1_dl.dl_info.frame_nr,
-			si := dec_SystemInformation(l1_dl.payload.data_ind.payload)
-		}
+
 		var integer tc := f_gsm_compute_tc(sig.frame_number);
 		log("SI received at TC=", tc, ": ", sig.si);
 		/* append to the per-TC bucket */
@@ -5227,17 +5223,13 @@
 runs on test_CT return SystemInformation {
 	var L1ctlDlMessage l1_dl;
 	var SystemInformation si;
+	var integer rc;
 	timer T := 5.0;
 	T.start;
 	alt {
 	[] pt.receive(tr_L1CTL_DATA_IND(t_RslChanNr_BCCH(0), ?)) -> value l1_dl {
-		/* somehow dec_SystemInformation will try to decode even non-RR as SI */
-		if (not (l1_dl.payload.data_ind.payload[1] ==  '06'O)) {
-			log("Ignoring non-RR SI ", l1_dl);
-			repeat;
-		}
-		si := dec_SystemInformation(l1_dl.payload.data_ind.payload)
-		if (si.header.message_type != si_type) {
+		rc := dec_SystemInformationSafe(l1_dl.payload.data_ind.payload, si);
+		if (rc != 0 or si.header.message_type != si_type) {
 			repeat;
 		}
 		}