grub2 for uefi

shim

grub2-efi

yum (re)install shim grub2-efi --installroot=/

remove all files underneath / exclude everything underneath ./boot/efi/EFI

rename ./boot/efi/EFI/redhat to ./boot/efi/EFI/QCT

patch ./boot/efi/EFI/QCT/*.CSV

Generate grub.cfg

for UEFI

rm -rf /dev/shm/firmware/*

mkdir -p /dev/shm/firmware/efi

mount -o bind /dev/shm/firmware /sys/firmware

grub2-mkconfig -o ./boot/efi/EFI/QCT/grub.cfg

umount  /sys/firmware

for Legacy

rm -rf /dev/shm/firmware/*

mkdir -p /dev/shm/firmware/

mount -o bind /dev/shm/firmware /sys/firmware

grub2-mkconfig -o ./boot/grub2/grub.cfg

umount  /sys/firmware

customize menuentry

/etc/os-release