diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index db0c2db..ff852eb 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -875,8 +875,12 @@
 		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");