Modify the startup time generation of grub in ubuntu

The starting time of online query modification of grub is basically modification/etc/default/grub

# Comment out GRUB_HIDDEN_TIMEOUT=0
#GRUB_HIDDEN_TIMEOUT=0
# Modify GRUB_TIMEOUT = 0 
GRUB_TIMEOUT = 0

Then run update-grub Regeneration/boot/grub/grub. cfg. However, this doesn't work, and you still have to wait 30 seconds

View/boot/grub/grub. cfg

### BEGIN /etc/grub.d/00_header ###
...
function recordfail {
 set recordfail=1
 # GRUB lacks write support for lvm, so recordfail support is disabled.
}
...
if [ "${recordfail}" = 1 ] ; then
 set timeout=30
...
if [ $grub_platform = efi ]; then
 set timeout=30
...
### END /etc/grub.d/00_header ###

As can be seen from the above configuration, if it is an lvm partition, the timeout time is 30 seconds; The timeout time is 30 seconds if it is started in EFI mode. Priority EFI > LVM.

Look again at the /etc/grub. d/00_header script that generated this configuration

...
  cat << EOF
if [ "\${recordfail}" = 1 ] ; then
 set timeout=${GRUB_RECORDFAIL_TIMEOUT:-30}
else
EOF
...
if [ "$recordfail_broken" = 1 ]; then
 cat << EOF
if [ \$grub_platform = efi ]; then
 set timeout=${GRUB_RECORDFAIL_TIMEOUT:-30}
 if [ x\$feature_timeout_style = xy ] ; then
  set timeout_style=menu
 fi
...

You can see that the timeout of 30 seconds is set with the value GRUB_RECORDFAIL_TIMEOUT.

So just add or modify GRUB_RECORDFAIL_TIMEOUT at/boot/grub/grub.cfg

GRUB_RECORDFAIL_TIMEOUT=0

Then run sudo update-grub Regeneration/boot/grub/grub. cfg.