diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index db0c2dbf7..ff852eb80 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -875,8 +875,12 @@ static int gsm48_rx_gmm_det_req(struct sgsn_mm_ctx *ctx, struct msgb *msg)
 		msgb_tlli(msg), get_value_string(gprs_det_t_mo_strs, detach_type),
 		power_off ? "Power-off" : "");
 
-	/* force_stby = 0 */
-	rc = gsm48_tx_gmm_det_ack(ctx, 0);
+	/* Only sent the Detach Accept (MO) if power off isn't indicated,
+	 * see 04.08, 4.7.4.1.2/3 for details */
+	if (!power_off) {
+		/* force_stby = 0 */
+		rc = gsm48_tx_gmm_det_ack(ctx, 0);
+	}
 
 	mm_ctx_cleanup_free(ctx, "GPRS DETACH REQUEST");
 
diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index 00ee86679..cb3c29472 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -213,7 +213,7 @@ static void test_gmm_detach_power_off(void)
 
 	/* verify that no message (and therefore no Detach Accept) has been
 	 * sent by the SGSN */
-	/* OSMO_ASSERT(sgsn_tx_counter_old == sgsn_tx_counter); */
+	OSMO_ASSERT(sgsn_tx_counter_old == sgsn_tx_counter);
 
 	/* verify that things are gone */
 	OSMO_ASSERT(count(gprs_llme_list()) == 0);