RE: Serial number during FOTA

tesc — Tue, 27 Apr 2021 12:10:35 GMT

Hi,

1. Giving each device a serial number through a FOTA BLE update is not a good idea.

2. The FOTA process will erase the full flash page containing the bootloader settings file. This is due to how flash works. The full page needs to be erased as part of updating its contents.

3. The issue of overwriting 0xFFFF0 is not the main issue. The issue is the value will get erased during the update process regardless.

4. There are several addresses in UICR that are made specifically for this purpose. See the CUSTOMER fields, from address 0x10001080 upwards on the nRF52840. They get programmed the same way as you program anything else onto the SoC using a Segger programmer.

Note also that there is a unique device identifier (DEVICEID) in the FICR flash page, written by us during production. Depending on your use case, using the value already in FICR may be just as good a solution as writing your own ID in UICR.

Regards,
Terje