diff --git a/openbsc/src/gprs/gprs_gb_parse.c b/openbsc/src/gprs/gprs_gb_parse.c
index adc07ff..2baaa06 100644
--- a/openbsc/src/gprs/gprs_gb_parse.c
+++ b/openbsc/src/gprs/gprs_gb_parse.c
@@ -279,6 +279,36 @@
 	return 1;
 }
 
+static int gprs_gb_parse_gmm_ra_upd_rej(uint8_t *data, size_t data_len,
+					struct gprs_gb_parse_context *parse_ctx)
+{
+	uint8_t *value;
+	uint8_t cause;
+	int force_standby;
+
+	parse_ctx->llc_msg_name = "RA_UPD_REJ";
+
+	/* GMM cause */
+	if (v_fixed_shift(&data, &data_len, 1, &value) <= 0)
+		return 0;
+
+	cause = value[0];
+
+	/* Force to standby, 1/2 */
+	/* spare bits, 1/2 */
+	if (v_fixed_shift(&data, &data_len, 1, &value) <= 0)
+		return 0;
+
+	force_standby = (value[0] & 0x07) == 0x01;
+
+	if (cause == GMM_CAUSE_IMPL_DETACHED && !force_standby)
+		parse_ctx->await_reattach = 1;
+
+	parse_ctx->invalidate_tlli = 1;
+
+	return 1;
+}
+
 static int gprs_gb_parse_gmm_ra_upd_ack(uint8_t *data, size_t data_len,
 					struct gprs_gb_parse_context *parse_ctx)
 {
@@ -418,6 +448,9 @@
 	case GSM48_MT_GMM_RA_UPD_REQ:
 		return gprs_gb_parse_gmm_ra_upd_req(data, data_len, parse_ctx);
 
+	case GSM48_MT_GMM_RA_UPD_REJ:
+		return gprs_gb_parse_gmm_ra_upd_rej(data, data_len, parse_ctx);
+
 	case GSM48_MT_GMM_RA_UPD_ACK:
 		return gprs_gb_parse_gmm_ra_upd_ack(data, data_len, parse_ctx);
 
diff --git a/openbsc/tests/gbproxy/gbproxy_test.c b/openbsc/tests/gbproxy/gbproxy_test.c
index cfbe688..a818a12 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.c
+++ b/openbsc/tests/gbproxy/gbproxy_test.c
@@ -2895,9 +2895,10 @@
 
 	dump_peers(stdout, 0, 0, &gbcfg);
 
-	/* TODO: This should have de-registered the TLLI which it did not. Add
-	 *       assertions when this is fixed.
-	 */
+	OSMO_ASSERT(!gbproxy_find_tlli(peer, local_tlli));
+	tlli_info = gbproxy_find_tlli_by_imsi(peer, imsi, sizeof(imsi));
+	OSMO_ASSERT(tlli_info);
+	OSMO_ASSERT(tlli_info->is_deregistered);
 
 	/* Bad case: Re-Attach with wrong (initial) P-TMSI */
 	send_llc_ul_ui(nsi, "ATTACH REQUEST", &bss_peer[0], 0x1002,
diff --git a/openbsc/tests/gbproxy/gbproxy_test.ok b/openbsc/tests/gbproxy/gbproxy_test.ok
index 0fb460b..65d868b 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.ok
+++ b/openbsc/tests/gbproxy/gbproxy_test.ok
@@ -4610,7 +4610,7 @@
     Attach Request count            : 4
     TLLI cache size                 : 1
     TLLI-Cache: 1
-      TLLI efe2b700 -> efe2b700, IMSI 12131415161718, AGE 0
+      TLLI 00000000, IMSI 12131415161718, AGE 0, DE-REGISTERED
 PROCESSING ATTACH REQUEST from 0x01020304:1111
 00 00 10 02 01 af e2 b7 00 00 00 04 08 88 11 22 33 40 50 60 12 34 00 80 0e 00 34 01 c0 39 08 01 02 f5 e0 21 08 02 05 f4 fb c5 46 79 11 22 33 40 50 60 19 18 b3 43 2b 25 96 62 00 60 80 9a c2 c6 62 00 60 80 ba c8 c6 62 00 60 80 00 e4 e8 65 
 
@@ -4629,7 +4629,7 @@
     TLLI cache size                 : 2
     TLLI-Cache: 2
       TLLI afe2b700 -> afe2b700, IMSI (none), AGE 0, STORED 1, IMSI acquisition in progress
-      TLLI efe2b700 -> efe2b700, IMSI 12131415161718, AGE 0
+      TLLI 00000000, IMSI 12131415161718, AGE 0, DE-REGISTERED
 PROCESSING ATTACH ACCEPT from 0x05060708:32000
 00 00 10 02 00 af e2 b7 00 00 50 20 16 82 02 58 13 99 18 b3 43 2b 25 96 62 00 60 80 9a c2 c6 62 00 60 80 ba c8 c6 62 00 60 80 00 0a 82 08 02 0d 88 11 12 13 14 15 16 17 18 00 81 00 0e 9e 41 c0 29 08 02 01 49 04 21 63 54 40 50 60 19 cd d7 08 17 16 18 05 f4 ef e2 b7 00 d2 d1 3e