diff --git a/src/trau/trau_sync.c b/src/trau/trau_sync.c
index 730cf0c..89c5558 100644
--- a/src/trau/trau_sync.c
+++ b/src/trau/trau_sync.c
@@ -499,7 +499,6 @@
 
 	tss->out_cb = frame_out_cb;
 	tss->user_data = user_data;
-	/* FIXME: this must be configurable */
 	tss->pattern = &sync_patterns[pat_id];
 
 	/* An unusued E1 timeslot normally would send an idle signal that
@@ -511,6 +510,14 @@
 	return fi;
 }
 
+void osmo_trau_sync_set_pat(struct osmo_fsm_inst *fi, enum osmo_tray_sync_pat_id pat_id)
+{
+	struct trau_rx_sync_state *tss = fi->priv;
+
+	tss->pattern = &sync_patterns[pat_id];
+	osmo_fsm_inst_state_chg(fi, FRAME_ALIGNMENT_LOST, 0, 0);
+}
+
 void osmo_trau_sync_rx_ubits(struct osmo_fsm_inst *fi, const ubit_t *bits, size_t n_bits)
 {
 	struct ubit_buf ubb;