first things first: if it happens to the user to have a gigabyte mainboard… with a PS2 keyboard connector and a BIOS UEFI that does not allow USB keyboards to be used right after start… get a PS2 keyboard (the user can test if keyboard is responding like this: hit NUM block activate/disable button (usually called NUM) multiple times… does the LED light on/off yes? (good) no? (bad get PS2 keyboard)

to modify the timeout (make boot faster)

grub2 debian boot screen splash image

on newer *.deb based GNU Linux (Debian, Ubuntu, Mint)

tested on : (# Debian 8 “Jessie” Linux DebianGiada 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt7-1 (2015-03-01) x86_64 GNU/Linux):

edit this config file:

vim /etc/default/grub

# modify 1 = wait 1 second until entry 0 is booted
# would also remove the "quiet" parameter to get more verbose output during boot
# (red in dmesg = usually something bad, but maybe system still works anyway X-D)

# while here, for privacy reasons the user might also wants to disable ipv6
# only needed by devices that are DIRECTLY connected to the internet like routers & servers
# to generate new /boot/grub/grub.cfg
# Debian/Ubuntu
# update-grub2 can not be found in Debian10?
# it is probably this problem
su - root
# try again

on *.rpm Fedora/CentOS/Redhat:

the command to re-generate the grub.cfg is different

# this used to be enough for CentOS7
grub2-mkconfig -o /boot/grub2/grub.cfg

on older debian / grub1

checkout this config file:

vim /boot/grub/menu.lst

related links:

grub2 during update – where to install grub2 boot loader – harddisk has changed