diff --git a/src/osmo-bsc/system_information.c b/src/osmo-bsc/system_information.c
index 086b8e9..18c609b 100644
--- a/src/osmo-bsc/system_information.c
+++ b/src/osmo-bsc/system_information.c
@@ -764,7 +764,7 @@
 
 	memset(si2b, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
 
-	si2b->header.l2_plen = GSM48_LEN2PLEN(22);
+	si2b->header.l2_plen = GSM48_LEN2PLEN(21);
 	si2b->header.rr_protocol_discriminator = GSM48_PDISC_RR;
 	si2b->header.skip_indicator = 0;
 	si2b->header.system_information = GSM48_MT_RR_SYSINFO_2bis;
diff --git a/tests/gsm0408/gsm0408_test.ok b/tests/gsm0408/gsm0408_test.ok
index 9424167..0c6df7a 100644
--- a/tests/gsm0408/gsm0408_test.ok
+++ b/tests/gsm0408/gsm0408_test.ok
@@ -213,7 +213,7 @@
 BTS allocation OK in test_si_ba_ind()
 Testing if BA-IND is set as expected in SI2xxx and SI5xxx
 SI2: 59 06 1a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e5 04 00 
-SI2bis: 59 06 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e5 04 00 2b 
+SI2bis: 55 06 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e5 04 00 2b 
 SI2ter: 59 06 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 2b 2b 2b 2b 
 SI5: 06 1d 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
 SI5bis: 06 05 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00