Gnu Grub 2.04 ignore countdown?

[mahesh]

Problem: I want to skip/edit the 10 seconds countdown/timeout timer when starting my laptop.

When I start my Ubuntu 20.04.3 laptop I get a menu with 4 options:

*Ubuntu
Advanced options for Ubuntu
Windows Boot Manager (on /dev/nvme0n1p2)
UEFI Firmware Settings


in /etc/default/grub, I have edit the text in by removing the hashtag and set
# GRUB_HIDDEN_TIMEOUT=0
# GRUB_HIDDEN_TIMEOUT_QUIET=true

However it does not have any effect on the countdown timer.

Please help me out.
Thanks!