ubuntu modify the grub boot time

Online query modification grub startup time is essentially modify / etc / default / grub

#注释掉GRUB_HIDDEN_TIMEOUT=0
#GRUB_HIDDEN_TIMEOUT=0
#修改GRUB_TIMEOUT = 0 
GRUB_TIMEOUT = 0

Then run the update-grub regenerate /boot/grub/grub.cfg. However, this is not effective , still have to wait for 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 ###

Can be seen from the above configuration, if the partition lvm, the timeout time of 30 seconds; if EFI boot mode timeout is 30 seconds priority EFI> LVM..

Look at this script configured to generate /etc/grub.d/00_header

...
    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
...

At this 30-second timeout can be seen by GRUB_RECORDFAIL_TIMEOUT this value set.
Therefore only need to add or modify /boot/grub/grub.cfg GRUB_RECORDFAIL_TIMEOUT

GRUB_RECORDFAIL_TIMEOUT=0

Then run sudo update-grubRegenerate /boot/grub/grub.cfg can be.