Boot a GNU/Linux installer on USB

How to boot from USB

Connect the USB drive. Check dmesg:
$ dmesg

Check that it wasn't automatically mounted. If it was, unmount it. For example:
$ sudo umount /dev/sdb1
# umount /dev/sdb1

dmesg told you what device it is. Overwrite the drive, writing your distro ISO to it with dd. For example:
$ sudo dd if=gnulinux.iso of=/dev/sdb bs=8M; sync
# dd if=gnulinux.iso of=/dev/sdb bs=8M; sync

Boot it in GRUB using the "Parse ISOLINUX config (USB)" option (it's in default libreboot grub.cfg, at least).

If the ISOLINUX parser won't work, then press C to get to GRUB command line.
ls
Get the device from above output, eg (usb0). Example:
cat (usb0)/isolinux/isolinux.cfg
Either this will show the ISOLINUX menuentries for that ISO, or link to other .cfg files, for example /isolinux/foo.cfg.
If it did that, then you do:
cat (usb0)/isolinux/foo.cfg
And so on, until you find the correct menuentries for ISOLINUX.

Now look at the ISOLINUX menuentry. It'll look like:

	  kernel /path/to/kernel
	  append PARAMETERS initrd=/path/to/initrd MAYBE_MORE_PARAMETERS

GRUB works the same way, but in it's own way. Example GRUB commands:
linux (usb0)/path/to/kernel PARAMETERS MAYBE_MORE_PARAMETERS
initrd (usb0)/path/to/initrd
boot
Of course this will vary from distro to distro. If you did all that correctly, it should now be booting the ISO the way you specified.

Troubleshooting

debian-installer (trisquel net install) graphical corruption in text-mode

When using the ROM images that use coreboot's "text mode" instead of the coreboot framebuffer, booting the Trisquel net installer results in graphical corruption because it is trying to switch to a framebuffer which doesn't exist. Use that kernel parameter on the 'linux' line when booting it:
vga=normal fb=false

Tested in Trisquel 6 (and 7). This forces debian-installer to start in text-mode, instead of trying to switch to a framebuffer.

If selecting text-mode from a GRUB menu created using the ISOLINUX parser, you can press E on the menu entry to add this. Or, if you are booting manually (from GRUB terminal) then just add the parameters.

This workaround was found on the page: https://www.debian.org/releases/stable/i386/ch05s04.html. It should also work for gNewSense, Debian and any other apt-get distro that provides debian-installer (text mode) net install method.

Copyright © 2014 Francis Rowe <info@gluglug.org.uk>
This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. A copy of the license can be found at ../license.txt.

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../license.txt for more information.