Bootloader
OTA also works on the RAK4631 with the preinstalled bootloader. If the process is interrupted for any reason, you’ll need to manually restart the RAK4631. In some cases, this may mean you’ll have to climb up to the repeater or room server. The new bootloader, on the other hand, boots back into DFU mode, allowing you to retry the OTA process.
With the Xiao nRF52, OTA does not work at all without the modified bootloader.
Checking the Bootloader Version
To identify the correct bootloader version, the device must be put into DFU mode.
In the mounted directory of the hardware, you will now find a file named “INFO_UF2.TXT.” It contains information about the hardware, the bootloader, and its version.
Update the bootloader
Updating the bootloader is quite simple. Nothing is deleted during the process, and all settings are preserved.
- Go to https://github.com/oltaco/Adafruit_nRF52_Bootloader_OTAFIX or https://github.com/oltaco/WisCore_RAK4631_Bootloader to download the appropriate bootloader for your hardware. This is usually an uf2 file.
- Next, connect the RAK4631 or Xiao nRF52 to the computer via a USB cable. Of course, you must first put the device into DFU mode.
- After that, the uf2 file can be copied to the device. The device will automatically reboot after the copy is complete, installing the bootloader in the process. An error message usually appears stating that the copy process failed. This can be ignored and is caused by the device’s automatic reset.
Performing an OTA Update
First, you must install the “nRF Device Firmware Update” app on your smartphone, tablet, laptop, etc.
- Apple: https://apps.apple.com/us/app/nrf-device-firmware-update/id1624454660
- Android: https://play.google.com/store/apps/details?id=no.nordicsemi.android.dfu
Go to https://meshcore.io/flasher to download the correct firmware for the device.
You’ll need to configure a few settings in the installed “nRF Device Firmware Update” app first:
- “Packet receipt notifications” must be enabled
- “Number of packets” must be set to 10
- “Force Scanning” must be enabled
Now the repeater or room server can be put into OTA mode in the MashCore app. To do this, log in to the corresponding device and enter “start ota” in the command line. In the “nRF Device Firmware Update” app, select the ZIP file you downloaded earlier. Under “Device,” you can now select your hardware and start the OTA process by clicking “Start.” After the update is complete, the device will reboot.
The OTA process may take a few minutes, so please be patient.