Install Linux on a Canoeboot system

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Booting Linux from GRUB payload

NOTE: This guide pertains to x86 hosts, and does not cover supported CrOS/ARM chromebooks. For ARM targets, you should refer to u-boot documentation - separate U-Boot x86 documentation is also available.

GRUB

This page is useful for those who wish to use the GRUB GRUB payload directly. If you’re using SeaBIOS, the boot process will work similarly to traditional BIOS systems; refer to the SeaBIOS documentation on https://seabios.org/SeaBIOS

Linux is generally assumed, especially for Canoeboot development, but Canoeboot also works quite nicely with BSD systems.

Refer to these pages, hosted by the Canoeboot project:

They will provide specific information; the information below pertains mostly to troubleshooting, and there are some notes about Full Disk Encryption:

Encrypted /boot via LUKS2 with argon2

Full encryption for basic LUKS2 (with PBKDF or argon2 key derivation) is supported in Canoeboot. Legacy LUKS1 is also supported. On most other systems, /boot must be unencrypted, but Canoeboot supports use of the GRUB bootloader as a coreboot payload, directly in the boot flash.

GRUB has code in it that can be used to unlock LUKS1 and LUKS2 dm-crypt, using the cryptomount command. With this, you can boot with true full disk encryption, by encrypting /boot.

This is a boon for security, because it’s harder to tamper with, and you could potentially write-protect plus maybe provide a password in GRUB at boot time.

The easiest way to use it is like this: in Linux, set up your partitions like you would, but use LVM volume groups, with group name grubcrypt and either:

If your distro then installs GRUB, and provides a grub.cfg file under /boot/grub (within the distro, on your SSD/HDD file system), it should work. Canoeboot’s GRUB will automatically give you a passphrase prompt, where you type your passphrase and it unlocks the volume. Then it will find your LVMs and it’ll boot from that.

Otherwise, to manually unlock it, you drop to the GRUB shell with C and do:

cryptomount -a

Or on a specific device, e.g.

cryptomount (ahci0,1)

This is similar to cryptsetup luksOpen in Linux.

Canoeboot GRUB merges the PHC argon2 implementation, so it has full support for LUKS2 installations in addition to LUKS1. Canoeboot 20231026 and higher has argon2 support, but older releases only supported PBKDF2 which would make LUKS2 dysfunctional unless you swapped it to use PBKDF2 (not argon2) and/or downgraded to LUKS1.

With modern Canoeboot, you can just use LUKS2 as-is, on most/all Linux distros. At the time of the Canoeboot 20231026 release, the GRUB upstream (on gnu.org) did not have these argon2 patches in its source tree, but Canoeboot merges and maintains them out of tree.

argon2id

You should specifically use argon2id. Please ensure this, because some older LUKS2 setups defaulted to the weaker argon2i. This post by Matthew Garret contains information about that:

https://mjg59.dreamwidth.org/66429.html

Canoeboot’s GRUB Argon2id implementation was created by Patrick Steinhardt, who adapted PHC’s Argon2 implementation for use in GRUB; Ax33l later added it to Arch Linux AUR for GRUB 2.06, and Nicholas Johnson rebased that for GRUB 2.12 so that Canoeboot could use it; Canoeboot later inherited it.

NOTE: You should also read the instructions about about GRUB_TERMINAL.

NOTE ABOUT VGA MODES and GRUB

Canoeboot does not support switching VGA modes, when coreboot’s libgfxinit is used on Intel GPUs. Many distros will install GRUB, which Canoeboot then finds and executes, if running SeaBIOS payload; if using GRUB, just the distro’s grub.cfg file is loaded instead, by Canoeboot’s own GRUB in flash.

Canoeboot GRUB boots in text mode or uses the coreboot framebuffer. Anyway, set GRUB_TERMINAL=console in GRUB and you should be fine. This avoids GRUB, the one provided by your distro, switching video modes.

In Debian for example (steps largely the same on other distros):

Edit /etc/default/grub as root, and uncomment or add the line:

GRUB_TERMINAL=console

Then still as root, do these commands:

export PATH="$PATH:/sbin"
update-grub

NOTE: update-grub is very much Debian-centric. Not all distros will have it. On Arch-based distros for instance, you might do:

grub-mkconfig -o /boot/grub/grub.cfg

Now your distro’s GRUB menu should work, when your distro’s GRUB bootloader is executed from Canoeboot’s SeaBIOS payload.

Rebooting system in case of freeze

Linux kernel has a feature to do actions to the system any time, even with it freezes, this is called a Magic SysRq keys. You can do these actions with Alt + Sysrq + Command. These are the actions:

If some of them don’t work, you have to enable it in the kernel command line paramter. So append sysrq_always_enabled=1 to your GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub

You can also run # sysctl kernel.sysrq=1 to enable them.

Fedora won’t boot?

This may also apply to CentOS or Redhat. Chroot guide can be found on fedora website

linux16 issue

Canoeboot’s default GRUB config sources fedora’s grub config grub.cfg (in /boot/grub2/grub.cfg), fedora by default makes use of the linux16 command, where it should be saying linux

Do this in fedora:

Open /etc/grub.d/10_linux

Set the sixteenbit variable to an empty string, then run:

grub2-mkconfig -o /boot/grub2/grub.cfg

BLS issue

With newer versions of fedora, scripts from grub package default to generating BLS instead of grub.cfg. To change that behaviour add following line to /etc/default/grub (or modify existing one if it already exists):

GRUB_ENABLE_BLSCFG=false

Then generate grub.cfg with:

grub2-mkconfig -o /boot/grub2/grub.cfg

These idiosyncrasies aside, Fedora is a great distro. It’s well-tested with the Canoeboot build system, and it boots up just fine.

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