Update README.md

README.md

@@ -32,7 +32,7 @@ itself is linked in the area from 0 to 4000, leaving flash memory from 21000 onw
 On reset, the bootloader gains control. It checks for the presence of an application program (by a magic number located at a known address.) If an application is not present, or the reset was of a type other than power on and there is a special key in memory, it sets a flag which will prevent the application program from being run. This enables the bootloader to be loaded without an application program or allows the application to programmatically invoke the bootloader.
 The bootloader then initialises the BLE stack, following which it regains control, then either starts the application program, or starts up its own BLE service. The bootloader service UUID is stored in a firmware file, so the bootloader client knows which service to look for. There are two BLE characteristics, one for control and one for data which are used to transfer the application to the bootloader. The bootloader decrypts the data using the CRYPTO hardware, and verifies a SHA-256 hash to confirm successful and complete programming. If all this is successful it will enable the application program, which will run on the next reset.
 ## Using the bootloader client app
-An Android app is included in this repository as an APK. This can be sideloaded onto an Android device that supports BLE to load firmware files into a target device.  To test this out you should build the bootloader as provided here, and flash it to your device with JTAG/SWD. Build the sample app and copy the app.fmw file to your Android device. Then run the OTA DFU app you just sideloaded and using the "Choose Device" button find the advertising target device, called BG_OTA_DFU. Tap on this, then use the "Choose File" button to choose the firmware file (Dropbox can be handy for this.) Then the "Flash Device" button should be enabled, and pressing it will send the firmware file to the target. On successful completion it will reset, and assuming you are using a release build of the bootloader, the application program will start running, advertising itself as BG_APP. The bootloader debug build never runs the application.
+An Android app is included in this repository as an APK. This can be sideloaded onto an Android device that supports BLE to load firmware files into a target device.  To test this out you should build the bootloader as provided here, and flash it to your device with JTAG/SWD. Build the sample app and copy the app.fmw file to your Android device. Then run the OTA DFU app you just sideloaded and using the "Choose Device" button find the advertising target device, called BG_OTA_DFU. Tap on this, then use the "Choose File" button to choose the firmware file (Dropbox can be handy for this.) Then the "Flash Device" button should be enabled, and pressing it will send the firmware file to the target. On successful completion it will reset, and the application program will start running, advertising itself as BG_APP.
 ## Re-entering DFU mode
 Once you have your application running, to re-enter DFU mode it needs to do something - the sample app has a characteristic for this purpose, and the OTA DFU Android app recognises this and will show a button "Enter DFU mode" when it detects this characteristic. Tapping the button will cause the application to reboot to DFU mode, then the BG_OTA_DFU device will reappear.
 ## Customising