diff --git a/radio/src/dmafifo.h b/radio/src/dmafifo.h
index f74aada04..d4aaef4d3 100644
--- a/radio/src/dmafifo.h
+++ b/radio/src/dmafifo.h
@@ -45,6 +45,9 @@ class DMAFifo
 
     bool isEmpty()
     {
+#if defined(SIMU)
+      return true;
+#endif
       return (ridx == N - stream->NDTR);
     }
 
diff --git a/radio/src/sbus.cpp b/radio/src/sbus.cpp
index ace6d7060..f2cddc188 100644
--- a/radio/src/sbus.cpp
+++ b/radio/src/sbus.cpp
@@ -73,6 +73,7 @@ void processSbusFrame(uint8_t * sbus, int16_t * pulses, uint32_t size)
 
 void processSbusInput()
 {
+#if !defined(SIMU)
   uint8_t rxchar;
   uint32_t active = 0;
   while (sbusGetByte(&rxchar)) {
@@ -94,4 +95,5 @@ void processSbusInput()
       }
     }
   }
+#endif
 }
diff --git a/radio/src/sbus.h b/radio/src/sbus.h
index 4ab46a084..5ef7359a5 100644
--- a/radio/src/sbus.h
+++ b/radio/src/sbus.h
@@ -26,6 +26,5 @@
 #define SBUS_MAX_FRAME_SIZE   28
 
 void processSbusInput();
-void processSbusFrame(uint8_t * sbus, int16_t * pulses, uint32_t size);
 
 #endif // _SBUS_H_