System Bootorder not found - grub menu disappeared

[j8a]

Hi, I do not way you have several lines different. I post the difference in the /etc/default/grub
GRUB_DEFAULT=0
GRUB_SAVEDEFAULT=true
GRUB_TIMEOUT_STYLE=menu
#GRUB_HIDDEN_TIMEOUT=0
#GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR='Linux Lite'
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

Also you have to uncomment
#GRUB_DISABLE_OS_PROBER="false"
whether you are experiencing troubles with your boot process.
It was disabled by security purposes but I think you must check this. Are you dual booting with Windows?

Hope this help, regards