Merge pull request #2330 from particle-iot/fix/gen3-monolithic-flash-…

…erase

[nrf52840] platform: we only need to erase user application when building in modular

platform/MCU/nRF52840/src/flash_mal.c

@@ -385,13 +385,15 @@ int FLASH_CopyMemory(flash_device_t sourceDeviceID, uint32_t sourceAddress,
     }
 #endif // SOFTDEVICE_MBR_UPDATES
 
+#ifdef MODULAR_FIRMWARE
     // Make sure to invalidate the compat application, otherwise we'll keep booting into the compat application
     // as it takes precedence
     if (module_function == MODULE_FUNCTION_USER_PART && destinationAddress == USER_FIRMWARE_IMAGE_LOCATION) {
         if (!FLASH_EraseMemory(destinationDeviceID, USER_FIRMWARE_IMAGE_LOCATION_COMPAT, INTERNAL_FLASH_PAGE_SIZE)) {
             return FLASH_ACCESS_RESULT_ERROR;
         }
     }
+#endif // MODULAR_FIRMWARE
 
     if (!FLASH_EraseMemory(destinationDeviceID, destinationAddress, dest_size)) {
         return FLASH_ACCESS_RESULT_ERROR;