Flashrom error when trying to unbrick with SuzyQ

Support
1

System Details

  • Device: Board: KANO, Acer Chromebook Plus Spin 714
  • OS: ArchLinux on another PC, Chromebook is bricked
  • Firmware Type: In the process of going from stock to coreboot + u-root/grub/other payload
  • Firmware Version: unable to access anymore

Summary of the Issue

First of all a huge thanks to @MrChromebox for the awesome information on his website and helping others to use their devices as they see fit.

State of the Chromebook: CCD is open, all write protection mechanisms disabled, battery and external power disconnected.

After a bad flash I am trying to reflash the stock firmware. Flashrom reports errors, upon closer examination, flashrom can not reliably read the flash (maybe even write). Maybe someone has seen this.

Steps to Reproduce

  1. Flash command

    flashrom -p raiden_debug_spi:target=AP -w /path/to/backup.bin

  2. flashrom reports:

    flashrom v1.7.0 (git:v1.7.0) on Linux 7.0.5-arch1-1 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

FISK: AP
Raiden target: 2,0
Found Winbond flash chip "W25Q256JV_M" (32768 kB, SPI) on raiden_debug_spi.
Reading old flash chip contents... done.
Updating flash chip contents... Erase/write done from 0 to 1ffffff
Verifying flash... FAILED at 0x0000017b! Expected=0xa0, Found=0x80, failed byte count from 0x00000000-0x01ffffff: 0xaf2
Your flash chip is in an unknown state.
Please report this to the mailing list at [email protected] or
on chat (see https://flashrom.org/contact.html for details), thanks!

  3. I did try to read and then verify multiple times, when I read a large enough portion there are always read errors. What stood out to me is that it was almost always bit flips (like in the example above)

Expected Behavior

I guess flashing without so many errors. My buest guess is to either write a script that flashes the chip in multiple increments or to buy an external programmer.

I have reproduced this behaviour with a DIY SuzyQ and one purchased from Fyralabs (both have NOT used a USB redriver, maybe this is the issue?)

Luckily for me, I have found a chip with the top marking W25Q256JVEM on the backside of the mainboard. Maybe I could clip to that? I have never done that, so any advice is highly appreciated.

Thank you guys :slight_smile:

2

some Brya-based boards (like banshee) require an extra step in order to flash reliably via SuzyQ, this may help with KANO as well:

Open a terminal using minicom to the EC console:
sudo minicom -D /dev/ttyUSB2
run: apshutdown
wait 5s
run: gpioset en_S5_rails 1

then flash using: sudo flashrom -p raiden_debug_spi:target=AP,custom_rst=True ...

depending on the board, the GPIO name to enable the S5 rails may be different. There’s a command you can run from the EC console (use help) to list the GPIO names if that one isn’t valid

3

It worked! Thank you so much your help! :slight_smile:

I might open a PR for your website in the coming days, maybe someone else can benefit from this information.

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