Here in this quick tip, I'll show you how to enter the GRUB boot menu while only one operating system, i.e. Ubuntu installed on the system.
- First Shut down your Laptop/Desktop.
- Next power it up again.
- Start tapping the Shift key soon after you see the UEFI /BIOS screen, tap multiple times.
- You should be able to access the GRUB menu.
Usually hitting the Shift key once at the right moment is enough. However, the precise moment is unknown, that's why you should keep tapping the Shift key.
Alternative method to enter GRUB menu
Shift key doesn’t work, then you need to edit the
/etc/default/grub file, and find the line
GRUB_TIMEOUT and edit it to below.
After adding the timeout, you've to update the GRUB to make the changes available in actual grub.cfg file.
This will wait for 10 seconds before booting the default operating system.
Also read the grub rescue tips for better understanding of GRUB bootloader.