Rusty ChromeOS user moving from dual-boot -> standalone Linux

Hello folks,

Years ago I set up a GalliumOS (SeaBIOS I think…) dual-boot using the Mr. Chromebox utilities on my Google Pixelbook. I recently pulled it out of the closet with the idea of turning it into a Debian laptop and am trying to figure out what exactly I need to do.

After reading the Mr. Chromebox site, I understand this can be done by using the Legacy Bootloader to install an .iso from a USB drive like a normal computer. I can run an installer no problem. However, I think I’d first want to reformat the dual boot partitions (one with ChromeOS, the other with GalliumOS) down to 1, and then install Debian from there? I ran fdisk -l from a VT2 terminal and saw a ~112GB disk which I assume is only the ChromeOS half of my disk.

What steps do I need to take to remove the dual boot partition (& whatever configuration might be associated) before I can (presumably) just follow a user guide on installing standalone Debian?

One last note, I actually forgot the login for my GalliumOS user, so I don’t think I have a way to run scripts etc there. I’ll have to work from ChromeOS/BIOS.

Here are the docs if you would like to run through them

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Feel free to check obviously with MrChromebox’s script, but there might not be any update to the SeaBIOS payload since when you installed it, so nothing you need to do there really. If you’re looking to remove ChromeOS anyway, you can actually just partition your disk from the Debian installer.

I will mention MrChromebox’s full UEFI firmware option. This would be replacing Google’s firmware completely instead of using Google firmware + SeaBIOS. MrChromebox does recommend using his UEFI firmware if you do not need to dual boot. Installing it will require you to first disable hardware write protection for your device. Again all of the information is in the docs.

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Thanks for your note. I looked into the UEFI FW you mentioned in the docs, looks like it’s recommended to use CCD Suzy-Q cable to disable write protect for my CR50 device (2017 Pixelbook). I’ve found guides online for building one with some soldering and a USB-C breakout board. Maybe I’ll attempt to do so in the future if it seems the benefits of UEFI vs Google FW are worth the effort.

For now, I just installed Debian straight from my existing SeaBIOS as you suggested. I tried to update the RW_LEGACY FW with the latest Mr Chromebox script, but got an error. Actually, it showed that WP was disabled (?), but I certainly haven’t used a Suzy-Q on this device before. Curious! Will likely investigate later and open a new thread if necessary.

Thanks again, aeonull