Chromebook not booting - Bootloader unlock

[Ben Mezger]

Hopefully this is the right place to ask, if not, please guide me where I could ask for this kind of help.

I have a Samsung arm Chromebook XE303C12, and I've been trying to unlock the bootloader. I have successfully unlocked my bootloader following this guide: http://krblogs.com/post/63809988096/bootloader-unlock-on-samsung-arm-chromebook

So far so good. Then, as far as I remember, I ran the following commands (very silly, apparently);

$ flashrom --wp-disable
$ set_gbb_flags.sh
$ set_gbb_flags.sh 0x489
$ flashrom --wp-enable
$ reboot

On reboot, I had the uboot prompt, like normal days, except there was an error;
# File not found /boot/vmlinux.uimg

I ran the follwing;

$ vboot_twostop

Expecting to run ChromeOS like it always did, but now, when trying to do this, it now rebooots back to uboot prompt, and if I try once more, it boots to what I believe to be SeaBIOS with errors (see video).

How can I fix this issue? How can I recover this?

Video: https://youtu.be/6Ee-YU8CmZU

[Mike Frysinger]

the output shown before running vboot_twostop looks normal to me.  it's how i've configured my device.  but when i run vboot_twostop, it tails into the normal payload and i get the dev mode screen.  i suspect you've broken your firmware so it crashes when it tries to run.

you did make a backup of your firmware like that page (and pretty much every one out there) told you to right ?

if you get a SD card, you should be able to install linux onto it and then boot it.  if it has a uImage, it'd be something like:

  set bootargs root=/dev/mmcblk0p1 rw loglevel=7

  ext2load mmc 0:8 ${loadaddr} uImage

  bootm

then you can get a root prompt to try and recover the firmware.

note: no ARM chromebook has SeaBIOS as it makes no sense -- SeaBIOS emulates a legacy x86 BIOS.  you're on a CPU, so there is no such system.  if anything, u-boot (what you're already in) is the "legacy" boot mode.

-mike

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[Ben Mezger]

Mike,

Thanks for the response, I did make a firmware backup as the link stated, though, unfortunately I lost this backup. To install the Linux image on a SD, do you mean any Linux distro (that supports arm)? Or is there any specific one? If I manage to boot Linux from SD, couldn't I just re-update the firmware to nv_image-snow, install a new Linux distro, and get up and running again? Or do I really need Chromium?

[Mike Frysinger]

yes, u-boot can boot any uImage which means it can boot any arm distro.  i boot Gentoo Linux on my sd card directly from u-boot.

once you have root, you can get a copy of the flashrom binary and try reflashing your firmware.  what you choose to do from there (keep running other Linux distros or go back to CrOS) is entirely up to you.

-mike

[Ben Mezger]

Hi Mike,

I didn't have time to try what you have told me before, however, I am trying to get this fixed for a few days now, but no success.
I have tried downloading the following image from the Debian wiki (https://wiki.debian.org/InstallingDebianOn/Samsung/ARMChromebook) however, it didn't work, then I tried the following: http://archlinuxarm.org/platforms/armv7/samsung/samsung-chromebook-2 it didn't work either, it tells me "File not found vmlinux.uimg", I have also tried what you wrote, and it gave me the same thing (except then I had a uImage not found). Can you give me some hopes here? I am trying everything I can, but no success. What to do? Do you have a .img file of the image you are using? So I can try booting that too?

Thanks