diff --git a/libraries/AP_HAL_ChibiOS/Util.cpp b/libraries/AP_HAL_ChibiOS/Util.cpp
index ce7b2cc83a..51b98cf3b3 100644
--- a/libraries/AP_HAL_ChibiOS/Util.cpp
+++ b/libraries/AP_HAL_ChibiOS/Util.cpp
@@ -182,6 +182,8 @@ uint64_t Util::get_hw_rtc() const
     return stm32_get_utc_usec();
 }
 
+#ifndef HAL_NO_FLASH_SUPPORT
+
 bool Util::flash_bootloader()
 {
     uint32_t fw_size;
@@ -228,6 +230,7 @@ bool Util::flash_bootloader()
     free(fw);
     return false;
 }
+#endif //#ifndef HAL_NO_FLASH_SUPPORT
 
 /*
   display system identifer - board type and serial number
diff --git a/libraries/AP_HAL_ChibiOS/Util.h b/libraries/AP_HAL_ChibiOS/Util.h
index b3d19c76ad..b1410131b1 100644
--- a/libraries/AP_HAL_ChibiOS/Util.h
+++ b/libraries/AP_HAL_ChibiOS/Util.h
@@ -83,6 +83,7 @@ private:
       get system clock in UTC microseconds
      */
     uint64_t get_hw_rtc() const override;
-
+#ifndef HAL_NO_FLASH_SUPPORT
     bool flash_bootloader() override;
+#endif
 };