diff --git a/plugins/quectel.c b/plugins/quectel.c
index a0e435b5..f19065b2 100644
--- a/plugins/quectel.c
+++ b/plugins/quectel.c
@@ -84,22 +84,15 @@ enum quectel_model {
 	QUECTEL_MC60,
 };
 
-enum quectel_state {
-	QUECTEL_STATE_INITIALIZING = 0,
-	QUECTEL_STATE_POST_SIM,
-	QUECTEL_STATE_READY,
-	QUECTEL_STATE_INITIALIZED,
-};
-
 struct quectel_data {
 	GAtChat *modem;
 	GAtChat *aux;
 	enum ofono_vendor vendor;
 	enum quectel_model model;
-	enum quectel_state state;
-	struct ofono_sim *sim;
-	enum ofono_sim_state sim_state;
+	struct at_util_sim_state_query *sim_state_query;
 	unsigned int sim_watch;
+	bool sim_locked;
+	bool sim_ready;
 
 	/* used by quectel uart driver */
 	GAtChat *uart;
@@ -195,6 +188,7 @@ static void quectel_remove(struct ofono_modem *modem)
 	ofono_modem_set_data(modem, NULL);
 	l_timeout_remove(data->init_timeout);
 	l_gpio_writer_free(data->gpio);
+	at_util_sim_state_query_free(data->sim_state_query);
 	g_at_chat_unref(data->aux);
 	g_at_chat_unref(data->modem);
 	g_at_chat_unref(data->uart);
@@ -238,6 +232,9 @@ static void close_serial(struct ofono_modem *modem)
 
 	DBG("%p", modem);
 
+	at_util_sim_state_query_free(data->sim_state_query);
+	data->sim_state_query = NULL;
+
 	g_at_chat_unref(data->aux);
 	data->aux = NULL;
 
@@ -534,6 +531,7 @@ static void dbus_hw_enable(struct ofono_modem *modem)
 static void qinistat_cb(gboolean ok, GAtResult *result, gpointer user_data)
 {
 	struct ofono_modem *modem = user_data;
+	struct ofono_sim *sim = ofono_modem_get_sim(modem);
 	struct quectel_data *data = ofono_modem_get_data(modem);
 	GAtResultIter iter;
 	int ready = 0;
@@ -574,42 +572,13 @@ static void qinistat_cb(gboolean ok, GAtResult *result, gpointer user_data)
 	l_timeout_remove(data->init_timeout);
 	data->init_timeout = NULL;
 
-	if (data->sim_state == OFONO_SIM_STATE_READY) {
-		/*
-		 * when initializing with a non-locked sim card, the sim atom
-		 * isn't created until now to avoid accessing it before the
-		 * modem is ready.
-		 *
-		 * call ofono_modem_set_powered() to make ofono call
-		 * quectel_pre_sim() where the sim atom is created.
-		 */
-		ofono_modem_set_powered(modem, true);
-	} else {
-		/*
-		 * When initialized with a locked sim card, the modem is already
-		 * powered up, and the inserted signal has been sent to allow
-		 * the pin to be entered. So simply update the state, and notify
-		 * about the finished initialization below.
-		 */
-		data->sim_state = OFONO_SIM_STATE_READY;
-	}
-
-	ofono_sim_initialized_notify(data->sim);
-
-	/*
-	 * If quectel_post_sim() has not yet been called, then postpone atom
-	 * creation until it is called. Otherwise create the atoms now.
-	 */
-	if (data->state != QUECTEL_STATE_POST_SIM) {
-		data->state = QUECTEL_STATE_READY;
+	if (data->sim_locked) {
+		ofono_sim_initialized_notify(sim);
 		return;
 	}
 
-	ofono_sms_create(modem, data->vendor, "atmodem", data->aux);
-	ofono_phonebook_create(modem, data->vendor, "atmodem", data->aux);
-	ofono_voicecall_create(modem, data->vendor, "atmodem", data->aux);
-	ofono_call_volume_create(modem, data->vendor, "atmodem", data->aux);
-	data->state = QUECTEL_STATE_INITIALIZED;
+	data->sim_ready = true;
+	ofono_modem_set_powered(modem, TRUE);
 }
 
 static void init_timer_cb(struct l_timeout *timeout, void *user_data)
@@ -627,115 +596,109 @@ static void sim_watch_cb(GAtResult *result, void *user_data)
 {
 	struct ofono_modem *modem = user_data;
 	struct quectel_data *data = ofono_modem_get_data(modem);
+	GAtResultIter iter;
+	const char *cpin;
 
 	DBG("%p", modem);
 
+	g_at_result_iter_init(&iter, result);
+
+	if (!g_at_result_iter_next(&iter, "+CPIN:"))
+		return;
+
+	g_at_result_iter_next_unquoted_string(&iter, &cpin);
+
+	if (g_strcmp0(cpin, "READY") != 0)
+		return;
+
 	g_at_chat_unregister(data->aux, data->sim_watch);
 	data->sim_watch = 0;
 
 	data->init_timeout = l_timeout_create_ms(500, init_timer_cb, modem, NULL);
-	if (!data->init_timeout) {
-		close_serial(modem);
-		return;
-	}
 }
 
-static enum ofono_sim_state cme_parse(GAtResult *result)
-{
-	struct ofono_error error;
-
-	decode_at_error(&error, g_at_result_final_response(result));
-
-	if (error.type != OFONO_ERROR_TYPE_CME)
-		return OFONO_SIM_STATE_RESETTING;
-
-	switch (error.error) {
-	case 5:
-	case 6:
-	case 7:
-	case 11:
-	case 12:
-	case 17:
-	case 18:
-		return OFONO_SIM_STATE_LOCKED_OUT;
-	case 10:
-		return OFONO_SIM_STATE_NOT_PRESENT;
-	case 13:
-	case 14:
-	case 15:
-		return OFONO_SIM_STATE_RESETTING;
-	default:
-		ofono_error("unknown cpin error: %i", error.error);
-		return OFONO_SIM_STATE_RESETTING;
-	}
-}
-
-static enum ofono_sim_state cpin_parse(GAtResult *result)
+static void cpin_cb(gboolean ok, GAtResult *result, gpointer user_data)
 {
+	struct ofono_modem *modem = user_data;
+	struct quectel_data *data = ofono_modem_get_data(modem);
+	const char *path = ofono_modem_get_path(modem);
 	GAtResultIter iter;
 	const char *cpin;
 
+	DBG("%p", modem);
+
+	if (!ok) {
+		close_serial(modem);
+		return;
+	}
+
 	g_at_result_iter_init(&iter, result);
 
-	if (!g_at_result_iter_next(&iter, "+CPIN:"))
-		return OFONO_SIM_STATE_RESETTING;
+	if (!g_at_result_iter_next(&iter, "+CPIN:")) {
+		close_serial(modem);
+		return;
+	}
 
 	g_at_result_iter_next_unquoted_string(&iter, &cpin);
 
-	if (g_strcmp0(cpin, "NOT INSERTED") == 0)
-		return OFONO_SIM_STATE_NOT_PRESENT;
+	if (g_strcmp0(cpin, "READY") == 0) {
+		data->init_timeout = l_timeout_create_ms(500, init_timer_cb,
+								modem, NULL);
+		return;
+	}
 
-	if (g_strcmp0(cpin, "READY") == 0)
-		return OFONO_SIM_STATE_READY;
+	if (g_strcmp0(cpin, "SIM PIN") != 0) {
+		close_serial(modem);
+		return;
+	}
 
-	return OFONO_SIM_STATE_LOCKED_OUT;
+	ofono_info("%s: sim locked", path);
+	data->sim_locked = true;
+	data->sim_watch = g_at_chat_register(data->aux, "+CPIN:",
+						sim_watch_cb, FALSE,
+						modem, NULL);
+	ofono_modem_set_powered(modem, TRUE);
 }
 
-static void cpin_query(gboolean ok, GAtResult *result, gpointer user_data)
+static void sim_state_cb(gboolean present, gpointer user_data)
+{
+	struct ofono_modem *modem = user_data;
+	struct quectel_data *data = ofono_modem_get_data(modem);
+	const char *path = ofono_modem_get_path(modem);
+
+	DBG("%p present %d", modem, present);
+
+	at_util_sim_state_query_free(data->sim_state_query);
+	data->sim_state_query = NULL;
+	data->sim_locked = false;
+	data->sim_ready = false;
+
+	if (!present) {
+		ofono_modem_set_powered(modem, TRUE);
+		ofono_warn("%s: sim not present", path);
+		return;
+	}
+
+	g_at_chat_send(data->aux, "AT+CPIN?", cpin_prefix, cpin_cb, modem,
+			NULL);
+}
+
+static void cfun_cb(gboolean ok, GAtResult *result, gpointer user_data)
 {
 	struct ofono_modem *modem = user_data;
 	struct quectel_data *data = ofono_modem_get_data(modem);
 
-	DBG("%p ok %i", modem, ok);
+	DBG("%p ok %d", modem, ok);
 
-	if (ok)
-		data->sim_state = cpin_parse(result);
-	else
-		data->sim_state = cme_parse(result);
-
-	/* Turn off the radio. */
-	g_at_chat_send(data->aux, "AT+CFUN=4", none_prefix, NULL, NULL, NULL);
-
-	switch (data->sim_state) {
-	case OFONO_SIM_STATE_LOCKED_OUT:
-		ofono_modem_set_powered(modem, true);
-		data->sim_watch = g_at_chat_register(data->aux, "+CPIN: READY",
-							sim_watch_cb, FALSE,
-							modem, NULL);
-		if (!data->sim_watch) {
-			ofono_error("failed to create sim watch");
-			close_serial(modem);
-			return;
-		}
-		break;
-	case OFONO_SIM_STATE_READY:
-		data->init_timeout = l_timeout_create_ms(500, init_timer_cb,
-							modem, NULL);
-		if (!data->init_timeout) {
-			ofono_error("failed to create qinitstat timer");
-			close_serial(modem);
-			return;
-		}
-		break;
-	case OFONO_SIM_STATE_RESETTING:
-	case OFONO_SIM_STATE_INSERTED:
-		g_at_chat_send(data->aux, "AT+CPIN?", cpin_prefix, cpin_query,
-				modem, NULL);
-		break;
-	case OFONO_SIM_STATE_NOT_PRESENT:
-		ofono_warn("%s: sim not present", ofono_modem_get_path(modem));
-		ofono_modem_set_powered(modem, true);
+	if (!ok) {
+		close_serial(modem);
+		return;
 	}
+
+	dbus_hw_enable(modem);
+	data->sim_state_query = at_util_sim_state_query_new(data->aux,
+						2, 20, sim_state_cb, modem,
+						NULL);
 }
 
 static void cfun_enable(gboolean ok, GAtResult *result, gpointer user_data)
@@ -750,9 +713,7 @@ static void cfun_enable(gboolean ok, GAtResult *result, gpointer user_data)
 		return;
 	}
 
-	dbus_hw_enable(modem);
-
-	g_at_chat_send(data->aux, "AT+CPIN?", cpin_prefix, cpin_query, modem,
+	g_at_chat_send(data->aux, "AT+CFUN=4", none_prefix, cfun_cb, modem,
 			NULL);
 }
 
@@ -1108,8 +1069,6 @@ static int quectel_disable(struct ofono_modem *modem)
 	g_at_chat_send(data->aux, "AT+CFUN=0", cfun_prefix, cfun_disable, modem,
 			NULL);
 
-	data->state = QUECTEL_STATE_INITIALIZING;
-
 	return -EINPROGRESS;
 }
 
@@ -1146,22 +1105,18 @@ static void quectel_set_online(struct ofono_modem *modem, ofono_bool_t online,
 static void quectel_pre_sim(struct ofono_modem *modem)
 {
 	struct quectel_data *data = ofono_modem_get_data(modem);
+	struct ofono_sim *sim;
 
 	DBG("%p", modem);
 
-	ofono_devinfo_create(modem, 0, "atmodem", data->aux);
-	data->sim = ofono_sim_create(modem, data->vendor, "atmodem", data->aux);
-	if (!data->sim)
-		return;
+	ofono_voicecall_create(modem, data->vendor, "atmodem", data->aux);
+	sim = ofono_sim_create(modem, data->vendor, "atmodem", data->aux);
 
-	switch (data->sim_state) {
-	case OFONO_SIM_STATE_LOCKED_OUT:
-	case OFONO_SIM_STATE_READY:
-		ofono_sim_inserted_notify(data->sim, true);
-		break;
-	default:
-		break;
-	}
+	if (data->sim_locked || data->sim_ready)
+		ofono_sim_inserted_notify(sim, true);
+
+	if (data->sim_ready)
+		ofono_sim_initialized_notify(sim);
 }
 
 static void quectel_post_sim(struct ofono_modem *modem)
@@ -1179,31 +1134,9 @@ static void quectel_post_sim(struct ofono_modem *modem)
 	if (gprs && gc)
 		ofono_gprs_add_context(gprs, gc);
 
-	/*
-	 * the sim related atoms must not be created until the modem is really
-	 * ready, so check the state here
-	 */
-	switch (data->state) {
-	case QUECTEL_STATE_INITIALIZING:
-		/*
-		 * the modem is still initializing, so postpone the atom
-		 * creation until qinistat_cb() determines the modem is
-		 * ready
-		 */
-		data->state = QUECTEL_STATE_POST_SIM;
-		return;
-	case QUECTEL_STATE_READY:
-		/* the modem is ready, so create atoms below */
-		break;
-	default:
-		return;
-	}
-
 	ofono_sms_create(modem, data->vendor, "atmodem", data->aux);
 	ofono_phonebook_create(modem, data->vendor, "atmodem", data->aux);
-	ofono_voicecall_create(modem, data->vendor, "atmodem", data->aux);
 	ofono_call_volume_create(modem, data->vendor, "atmodem", data->aux);
-	data->state = QUECTEL_STATE_INITIALIZED;
 }
 
 static void quectel_post_online(struct ofono_modem *modem)