diff --git a/src/sgsn/gprs_mm_state_gb_fsm.c b/src/sgsn/gprs_mm_state_gb_fsm.c
index 02f6747..f6d680c 100644
--- a/src/sgsn/gprs_mm_state_gb_fsm.c
+++ b/src/sgsn/gprs_mm_state_gb_fsm.c
@@ -47,9 +47,11 @@
 
 	switch(event) {
 	case E_MM_READY_TIMER_EXPIRY:
-	case E_MM_IMPLICIT_DETACH:
 		mm_state_gb_fsm_state_chg(fi, ST_MM_STANDBY);
 		break;
+	case E_MM_IMPLICIT_DETACH:
+		mm_state_gb_fsm_state_chg(fi, ST_MM_IDLE);
+		break;
 	case E_MM_PDU_RECEPTION:
 		/* RE-arm the READY timer upon receival of Gb PDUs */
 		t_secs = osmo_tdef_get(sgsn->cfg.T_defs, 3314, OSMO_TDEF_S, -1);