Knowledge Base:Adjusting GRUB settings for a single boot session

Synopsis
When troubleshooting boot failures or trying to make changes for kernel settings, users might want to boot their system with a particular change in the GRUB bootloader configuration for a single boot session (i.e. not persistent).

Environment
Gentoo Linux systems using GRUB as the bootloader.

Analysis
With GRUB, it is possible to boot with different settings for just a single boot session. Changes made herein are not persisted, so rebooting afterwards will boot back using the "old" configuration settings.

Resolution

 * 1) During bootup, wait until you get to the GRUB boot menu.
 * 2) Navigate to the entry you want to boot from, but do not hit . Instead, press  (which stands for edit)
 * 3) Navigate to the line that you want to edit (which is most likely the one starting with , but can also be the   or   line) and hit  again to edit this specific line. When you are done changing the line, press.
 * 4) When you are done changing the line(s), press  to boot the entry

If you are happy with the result, do not forget to update  with the same changes to persist them.