Correct procedure to make a custom centos stream 8 iso UEFI bootable

Issues related to applications and software problems and general support
MustafaKamaal
Posts: 5
Joined: 2022/05/04 06:09:26

Re: Correct procedure to make a custom centos stream 8 iso UEFI bootable

Post by MustafaKamaal » 2022/05/10 09:24:02

Hi everyone,

I've tried both methods and have been able to make a bootable iso that's detectable in both Legacy BIOS and UEFI.
However, the change I made to EFI/BOOT/grub.cfg doesn't reflect when I select the boot options.

Original grub.cfg had the following snippet:

Code: Select all

menuentry 'Install CentOS Stream 8-stream' --class fedora --class gnu-linux --class gnu --class os {
        linuxefi /images/pxeboot/vmlinuz inst.stage2=hd:LABEL=CentOS-Stream-8-x86_64-dvd quiet
        initrdefi /images/pxeboot/initrd.img
}
I changed this to this:

Code: Select all

menuentry 'Install with Kickstart' --class fedora --class gnu-linux --class gnu --class os {
        linuxefi /images/pxeboot/vmlinuz inst.stage2=hd:LABEL=CentOS-Stream-8-x86_64-dvd inst.ks=hd:LABEL=CentOS-Stream-8-x86_64-dvd:/ks.cfg quiet
        initrdefi /images/pxeboot/initrd.img
}
And still I don't see the above mentioned change within UEFI boot menu.

I noticed that we give "images/efiboot.img" for the -e option.

I tried mounting "images/efiboot.img" using:

Code: Select all

mount -t auto images/efiboot.img /mnt/fat_in_iso/
And then I tried to look into the "/mnt/fat_in_iso/", it had the following file structure:

Code: Select all

.
└── EFI
    └── BOOT
        ├── BOOT.conf
        ├── BOOTIA32.EFI
        ├── BOOTX64.EFI
        ├── fonts
        │   └── unicode.pf2
        ├── grub.cfg
        ├── grubia32.efi
        ├── grubx64.efi
        ├── mmia32.efi
        └── mmx64.efi

3 directories, 9 files
I checked inside "EFI/BOOT/grub.cfg" and saw that it wasn't changed.

Shouldn't I be editing the grub.cfg inside "images/efiboot.img" ? Since I'm using it to package the ISO as UEFI bootable?

Some articles I read told me to edit BOOTX64.conf which didn't exist and I've tried editing the "EFI/BOOT/BOOT.conf" as well, but none reflected the changes to include the kickstart.

I'm kind of confused on this part because changes in isolinux/isolinux.cfg reflect properly.

Post Reply