diff --git a/targets/RT/USER/lte-softmodem.h b/targets/RT/USER/lte-softmodem.h
index 5cc4d5fea2..19d35263de 100644
--- a/targets/RT/USER/lte-softmodem.h
+++ b/targets/RT/USER/lte-softmodem.h
@@ -245,7 +245,7 @@ extern void stop_eNB(int);
 extern void kill_eNB_proc(int inst);
 
 // In lte-ru.c
-extern void init_RU(const char*);
+extern void init_RU(const char*,clock_source_t clock_source,clock_source_t time_source);
 extern void init_RU_proc(RU_t *ru);
 extern void stop_RU(int nb_ru);
 extern void kill_RU_proc(int inst);