File: //etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL="serial console"
GRUB_TERMINAL_OUTPUT="serial console"
GRUB_CMDLINE_LINUX="crashkernel=2G-8G:256M,8G-16G:512M,16G-:768M console=ttyS0,115200 console=tty0 panic=5 net.ifnames=0 biosdevname=0 intel_idle.max_cstate=1 intel_pstate=disable processor.max_cstate=1 amd_iommu=on iommu=pt"
GRUB_DISABLE_RECOVERY="true"
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"