[CentOS] USB ISO for CentOS 8

Fri Oct 4 15:44:13 UTC 2019
Young, Gregory <gregory.young at solarwinds.com>

You will want to follow the instructions for creating a custom .iso

^^^ Requires a Red Hat account, or Red Hat Developer Account.

The keys are to modify both:

- /isolinux/isolinux.cfg - for legacy BIOS boot
- /EFI/BOOT/grub.cfg - for UEFI boot

Make sure not to change the Volume Label, as this can mess up the UEFI boot

Then generate the .iso:

# cd /tmp/rhel7/
# mkisofs -o /tmp/rhel7test.iso -b isolinux/isolinux.bin -J -R -l -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e images/efiboot.img -no-emul-boot -graft-points -V "RHEL-7.7 Server.x86_64"  .

^^^ Change the "-V" label accordingly for CentOS 8 to match the CentOS 8 disk label.

And the critical command for USB drive booting:

# isohybrid --uefi /tmp/rhel7test.iso

Gregory Young 

-----Original Message-----
From: CentOS <centos-bounces at centos.org> On Behalf Of Jerry Geis
Sent: October 4, 2019 11:30 AM
To: CentOS mailing list <centos at centos.org>
Subject: [CentOS] USB ISO for CentOS 8

I did the dd of the ISO to a 16G USB device.

the second partition is FAT so I can edit it - I want to make a custom menu entry.
I edited the grub.cfg - but that did not work - my menu option does not show.

Then I think I need to change BOOT.cfg and generate the grub.cfg - but I dont know in this case how to generate for the USB device.

What command do I use for that ?

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