Some SPI Flash Chip Nuances Worth Learning

Some hackers have the skills to help us find noteworthy lessons in even the most basic of repairs. For instance, is your computer failing to boot? Guess what, it could just be a flash chip that’s to blame — and, there’s more you should know about such a failure mode. [Manawyrm] and [tSYS] over at the Kittenlabs blog show us a server motherboard fix involving a SPI flash chip replacement, and tell us every single detail we should know if we ever encounter such a case.

They got some Gigabyte MJ11-EC1 boards for cheap, and indeed, one of the BIOS chips simply failed — they show you how to figure that one out. Lesson one: after flashing a SPI chip, remember to read back the image and compare it to the one you just flashed into it! Now, you might be tempted to take any flash chip as a replacement, after all, many are command-compatible. Indeed, the duo crew harvested a SPI chip from an ESP32 board, the size matched, and surely, that’d suffice.

That’s another factor you should watch out for. Lesson two is to compare the SPI flash commands being used on the two chips you’re working with. In this case, the motherboard would read the BIOS alright and boot just fine, but wasn’t able to save the BIOS settings. Nothing you couldn’t fix by buying the exact chip needed and waiting for it to arrive, of course! SPI flash command sets are fun and worth learning about — after all, they could be the key to hacking your “smart” kettle. Need a 1.8 V level shifter while flashing? Remember, some resistors and a NPN transistor is more than enough.



from Blog – Hackaday https://ift.tt/PK4C9UM

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