Hello,
We have nRF52832 devices in the field, and one of the leading causes of warranty returns is that flash of nRF52 is completely erased. nrfjprog --readcode and --readuicr produce files filled with "0xFF".
This affects less than 0.1 % of all devices, but it's one of the most frequent issues we have. The devices have passed production testing and their data has been recorded to our production database, so it is impossible that the devices would not have been programmed when they left the factory floor.
The returned devices have drained batteries, possibly because the device with empty flash does not sleep the processor. It also might be that empty battery somehow triggers the emptying of the flash.
Our code uses softdevice page erase calls and fds garbage collect, which uses internally sd_flash_page_erase if I have understood correctly. Bootloader should protect the flash application outside of application area too, but I'm not ruling out a software bug.
Have you heard of similar issues before? Is it related to hardware or software? Any ideas on how we could further debug this?
Possibly related question https://devzone.nordicsemi.com/f/nordic-q-a/83503/nrf52832-sdk15-3-flash-erased-at-the-end-addresses-application-runs-but-bootloader-cannot-be-entered/346975#346975, we have also issues with partial flash erase.
