diff --git a/src/gos/freertos.c b/src/gos/freertos.c
index 872807d1..e3be4f28 100644
--- a/src/gos/freertos.c
+++ b/src/gos/freertos.c
@@ -107,6 +107,20 @@ bool_t gfxSemWait(gfxSem* psem, delaytime_t ms)
 	return FALSE;
 }
 
+bool_t gfxSemWaitI(gfxSem* psem)
+{
+	portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
+
+	psem->counter--;
+
+	if (xSemaphoreTakeFromISR(psem->sem,&xHigherPriorityTaskWoken) == pdTRUE)
+		return TRUE;
+
+	psem->counter++;
+
+	return FALSE;
+}
+
 void gfxSemSignal(gfxSem* psem)
 {
 	taskENTER_CRITICAL();
diff --git a/src/gos/freertos.h b/src/gos/freertos.h
index dc98185f..f15ca910 100644
--- a/src/gos/freertos.h
+++ b/src/gos/freertos.h
@@ -94,6 +94,7 @@ void gfxSleepMicroseconds(delaytime_t ms);
 void gfxSemInit(gfxSem* psem, semcount_t val, semcount_t limit);
 void gfxSemDestroy(gfxSem* psem);
 bool_t gfxSemWait(gfxSem* psem, delaytime_t ms);
+bool_t gfxSemWaitI(gfxSem* psem);
 void gfxSemSignal(gfxSem* psem);
 void gfxSemSignalI(gfxSem* psem);
 #define gfxSemCounterI(psem)		((psem)->counter)