This is a simple example of how to create a bootable ISO for a computer using UEFI. A makefile is included which automates the downloading of a test Linux kernel and initfs (Slackware current 64bit) and generating the bootable ISO and requisite files/images using the base tools.
The general flow of creating a bootable ISO for UEFI systems is:
- Create an UEFI Grub image with a stub config and minimal modules.
- Create a vfat image file to use as the UEFI ESP (EFI System Partition).
- Create the ISO with the kernel images, ESP image file, Grub modules, and full using mkisofs.
Create directories and change CWD:
mkdir -p efibootiso
cd efibootiso
mkdir -p EFI/BOOT
mkdir -p boot/grub/x86_64-efi
Download Slackware files:
curl \
-o boot/vmlinuz \
https://mirrors.kernel.org/slackware/slackware64-current/kernels/huge.s/bzImage
curl \
-o boot/initrd.img \
https://mirrors.kernel.org/slackware/slackware64-current/isolinux/initrd.img
Copy grub modules:
cp /usr/lib64/grub/x86_64-efi/*.mod boot/grub/x86_64-efi/
Create stub grub configuration:
cat << EOF > grub-stub.cfg
#################################################################
# the following insmod lines was disabled.
# See "donno" post in the issues section on the original
# github repository https://github.com/syzdek/efibootiso
#################################################################
#insmod all_video
#insmod efi_gop
#insmod efi_uga
#insmod video_bochs
#insmod video_cirrus
#insmod iso9660
#insmod udf
search --no-floppy --label EFIBOOTISO --set root
set prefix=($root)/boot/grub
configfile /grub.cfg
EOF
Create grub image:
grub-mkimage \
-o EFI/BOOT/bootx64.efi \
-c grub-stub.cfg \
-p /boot/grub \
-O x86_64-efi \
all_video disk part_gpt part_msdos linux normal configfile \
search search_label efi_gop fat iso9660 cat echo ls test \
true help gzio multiboot2 efi_uga reboot halt lspci
#################################################################
# the following module lines was disabled.
# See "donno" post in the issues section on the original
# github repository https://github.com/syzdek/efibootiso
#################################################################
#efi_gop efi_uga efinet \
#all_video video video_bochs video_cirrus video_fb videoinfo \
#serial \
#terminfo terminal \
#search search_fs_file search_fs_uuid search_label \
#udf iso9660 ext2 fat exfat ntfs hfsplus \
#part_gpt part_msdos msdospart lvm diskfilter parttool probe \
#normal \
#acpi ohci uhci ahci ehci \
#cat ls chain configfile echo halt reboot \
#ls lsefimmap lsefisystab lsmmap lspci lsacpi lssal \
#linux
Create empty file to use as disk image:
dd if=/dev/zero of=EFI/BOOT/efiboot.img bs=512 count=2880
Create MSDOS filesystem:
mkfs.msdos -F 12 -n 'EFIBOOTISO' EFI/BOOT/efiboot.img
Create directory structure:
mmd -i EFI/BOOT/efiboot.img ::EFI
mmd -i EFI/BOOT/efiboot.img ::EFI/BOOT
Copy grub image into disk image file:
mcopy -i EFI/BOOT/efiboot.img EFI/BOOT/bootx64.efi ::EFI/BOOT/bootx64.efi
Create full grub configuration:
cat << EOF > grub.cfg
serial --unit 4 --speed 9600
terminal_input serial console
terminal_output serial console
set pager=1
menuentry --hotkey=l 'Linux' {
echo 'Loading /boot/vmlinuz ...'
linux /boot/vmlinuz \
console=tty0 \
rw
echo 'Loading /boot/initrd.img ...'
initrd /boot/initrd.img
}
menuentry --hotkey=p 'List PCI' {
lspci
}
menuentry --hotkey=r 'Reboot' {
reboot
}
menuentry --hotkey=h 'Halt' {
halt
}
EOF
Create ISO image with mkisofs:
mkisofs \
-o efiboot.iso \
-R -J -v -d -N \
-x efiboot.iso \
-hide-rr-moved \
-no-emul-boot \
-eltorito-platform efi \
-eltorito-boot EFI/BOOT/efiboot.img \
-V "EFIBOOTISO" \
-A "EFI Boot ISO Test" \
.