How to override grub and boot to Ubuntu directly (from UEFI or windows)?

I recently changed the grub parameters to this (via grub manager):

GRUB_HIDDEN_TIMEOUT=0.0 GRUB_TIMEOUT=0.0 

because I wanted GRUB to shows only if I pressed shift and I wanted my pc to automatically boot to windows if I didn't press anything.

Unfortunately I can't display GRUB by pressing Shift on start, my pc automatically boot to windows and I can't go back to Ubuntu to change the setting.

(It's normal that it boot to windows automatically because I specified it in the GRUB settings)

Do you know a way to either access grub or access Ubuntu ?

I tried to boot override from UEFI to Ubuntu but I still go to windows...

Thank you.

1 Answer

The first step is to install a Windows program to access Linux partitions from within Windows as described here: (Best way to access ext partion in windows)

The next step is to edit /boot/grub/grub.cfg and search for timeout changing the value from 0 to 5.

Save the file and reboot.

Note that after rebooting Ubuntu you still need to change /etc/default/grub otherwise the next time you run sudo update-grub the timeout will go back to zero.