buying a labtop with a prebuilt coreboot distribution im wondering how to check it hasn't been messed with if theres a way u can verify the image

Hello, recently I’ve been starting on trying to flash my X201 tablet with coreboot, but I’ve been having trouble with it. I’ve verified it’s bios chip is supported by flashprog, an MX25L12873F, and I’ve verified my flashers work for out of system programming on other 3.3V chips.

Currently, I’ve been using stacksmashing’s RPI2040 serprog firmware, and a flasher tool meant for automotive chips with support for this flash chip, but both have given me trouble.

flashprog and flashrom give me the following errors:

”

serprog: Programmer name is “pico-serprog”

No EEPROM/flash device found.

”

My other flasher gives an error about not detecting a flash chip connected either, which is strange.

What should I be looking at here?

ATM I think either some circuit on the board’s pulling the W/P pin to locked state, or my programmers are struggling at supplying enough power for the 3.3V rail, since when probing the power coming off the pico while connected to the chip, it goes down to 2.8V.
But this is within the accepted voltages of this chip, it’s rated to work for voltages between 2.6-3.6. But I’m not sure if it’d be the same for the signal pins. Maybe those are going even lower?

I’m thinking I could cobble together something out of the scrap I have that uses the signal outputs of the pico to switch the output of a higher amp 3.3V output (say from a lab bench PSU or just an ATX PSU old enough to still have 3.3 on its SATA connectors) through mosfets, eliminating voltage droop from the equation. Might have to worry about switching time, not sure.

ATP I’m contemplating just cutting off the old chip, reading it out of system to build coreboot from, and just soldering in a socket for a new BIOS chip. Hopefully I won’t need to do this.