I have been using the flash-eeprom library for some time now to emulate about 1.5KBytes of eeprom. I have two cores (an old one and a recent one) and my colleague has an old core as well. The flash-eeprom was working well on my old core for a while, but then it started to die. Not the core – it works fine. It’s just that the data written to flash via flash-eeprom would not come back reliably after power cycling and the problem got worse with time and now flash doesn’t store at all. OK, a hardware problem. So now I’m trying this on the new Core and only part of my data stores correctly in non-volatile memory. The same firmware seems to still work fine on my colleague’s older core.
Is there some production hardware problem with the 2MB external flash that flash eeprom uses? Has the flash eeprom library been changed recently (or the underlying libraries - perhaps flash storage timing)? Is there a simply, guaranteed to work test program that tests emulated eeprom through flash eeprom that I can use to see if there is a hardware problem with my cores or not? Is there a know hardware problem here and perhaps I should just wait for my photon to arrive, since the photon does not have this external flash chip?