Boot Failed or Iso generation fails

Hi all,

just found this guide [Edit and repack .iso bootable image · GitHub]

But my Rocky Linux 8.9 dvd iso doesn’t boot correctly.
Screen prints this:

Booting from Disk connected to front USB 1: v212w
Booting failed: Disk connected to front USB 1: v212w

Boot Failed:
Please ensure a compatible bootable media is available.

I mount the USB with this linux command:

dd if=/image_directory/image.iso of=/dev/sda

using sda as my usb mounts there. Can someone tell me how to modify a iso so i can add a kickstart and grub file?

Also don’t understand fully what is ment here when running the command:

$ isohybrid /tmp/output.iso
isohybrid: Warning: more than 1024 cylinders: 13213
isohybrid: Not all BIOSes will be able to boot this device

Have also tried using Rawrite32 and Fedore Writer on my Win 10 but the result is the same.

Also found A bash program to securely create a bootable USB device from one image file.

you can install by:

curl -L -O
chmod +x bootiso

Then just ./bootiso ./your.iso But it comes with this error out.

bootiso: Found non-hybrid image; inspecting image for boot capabilities…
find: ‘/usr/lib/syslinux’: No such file or directory
find: ‘/usr/lib/syslinux’: No such file or directory
find: ‘/usr/lib/syslinux’: No such file or directory
bootiso: Could not find a SYSLINUX bios folder containing c32 bios module files on this system. Exiting…
bootiso: See bootiso/ at master · jsamr/bootiso · GitHub

How can i make sure the iso is ready for use?

Note that after writing an ISO to a USB, you should in theory be able to just add your kickstart and custom grub files and test it that way. But you must not modify the ISO before hand using mkisofs.

The guide you posted about repacking an ISO is not the best way to do for Rocky Linux. If you want to repack an iso, considering using xorriso, with the correct options, to avoid damaging the iso.

If you’re wanting to do the kickstart and some custom grub file before writing to a USB, use pure xorriso.

/usr/bin/xorriso \
 -indev /path/to/old_iso.iso \
 -outdev /path/to/new_iso.iso \
 -boot_image any replay \
 -joliet on \
 -system_id LINUX \
 -compliance joliet_long_names \
 -volid Rocky-8-9-x86_64-dvd \
 -map /path/to/kickstart.ks ks.cfg
 -map /path/to/grub2.cfg EFI/BOOT/grub.cfg
 -map /path/to/grub.conf isolinux/grub.conf

Please use dd or other supported methods.