I’m using a super simple piece of code to persist my target temperature or at least trying to. writing: int setTargetTemp(String command) { target = command.toFloat(); double targetWrite = target; EEPROM.put(0,target); return 1; } reading: double target = 0; void setup() { Spark.va…

@nicodegunst nice catch! Section 3.3 is of specific interest IMO. I’ll flag the folks at Particle. :grinning:

Thanks! And that section in particular drew my attention to. I can not find the mentioned routine “EE_Init()” anywhere in the firmware, so maybe this can be of any use somewhere somehow. I hope it will get a higher priority soon. I receiving more and more reports from users now, so it is getting ve…

@nicodegunst , that is a really good article and quite sobering. The STM32 has brownout voltage detection and I’m not sure it is being used. :smile:

I have tried to turn it on/change its settings, I have added: FLASH_OB_BORConfig(OB_BOR_LEVEL3); to setup(). But could not really notice any difference between one or the other. I could still reproduce the problem, regardless of this setting. I also tried enabling/disabling write protect FLASH_…

That app note talks about recovering from power loss/brown-out during the update window. Whether or not the particle code is susceptable to these errors, I have no idea, but this can be fixed so that at worst you lose the last update and have to roll back to the previous version. I believe the par…

I can confirm it happens when no (user code) write actions are being performed. I do not write to “EEPROM” on boot, and it always happens when (un)plugging a device from a (charged) battery power source. Are there any write actions in the photon firmware at boot time?

As I suspected, thank you for the confirmation.

A detailed description of how to reproduce this, including test firmware, would be a great first step in our journey towards a fix.

Seems like we have plenty of reproduction listings in this thread. I can ship you a USB wallwart that causes this issue it if you want?

I was able to reproduce pretty easy using a USB cable with a broken micro-usb connector. It has a bad connector, so I just have to tap it to cut power. It hardly ever happens when cutting power when the photon has reached user code. But when cutting power while the LED is white, the eeprom would be…

'EEPROM' persistence issue

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'EEPROM' persistence issue

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