I am using the AT45DB641B Adesto DataFlash and not in Low Power mode.
In my application I am recording a stream of raw sensor data and constantly writing to flash every second. I have a self-test that is invoked every minute to read back a sentinel from flash to make sure everything is running correctly. However, when I have been running my recording for from between 10 minutes up to 4 hours, at some point the flash would read back all zeros at this sentinel address. This memory address is set once initially and is never modified during the course of the recording.
In my test unit, I exercise heavily erase/program then read back and different set of data and all operations seem to work normally.
I wonder what could possibly cause a flash to read back zeros and that it happens inconsistently.