Re: [CentOS] USB ISO for CentOS 8
Nope, that editable FAT partition is actually the EFI boot partition. IIRC, the grub config in that partition isn't actually used, only the EFI bootstrap files. Once it can access the config on the main .iso partition it loads everything from there. Gregory Young -Original Message- From: CentOS On Behalf Of Jerry Geis Sent: October 4, 2019 1:08 PM To: CentOS mailing list Subject: Re: [CentOS] USB ISO for CentOS 8 >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 I was "thinking" all that was not needed - the second partition is "editable" - I change the file - I just need to regenerate grub right - not the whole ISO. I was hoping that is why they split this out into two partitions - for just such an occasion? Just want to add a menu option. THanks, Jerry ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] USB ISO for CentOS 8
>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 I was "thinking" all that was not needed - the second partition is "editable" - I change the file - I just need to regenerate grub right - not the whole ISO. I was hoping that is why they split this out into two partitions - for just such an occasion? Just want to add a menu option. THanks, Jerry ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] USB ISO for CentOS 8
On 10/4/19 5:30 PM, Jerry Geis wrote: > 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. If you boot via UEFI, you need to edit differnt grub.cfg, EFI/BOOT/grub.cfg not isolinux/grub.cfg > > 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 ? > Thanks, > > Jerry > ___ > CentOS mailing list > CentOS@centos.org > https://lists.centos.org/mailman/listinfo/centos > -- Ljubomir Ljubojevic (Love is in the Air) PL Computers Serbia, Europe StarOS, Mikrotik and CentOS/RHEL/Linux consultant ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] USB ISO for CentOS 8
You will want to follow the instructions for creating a custom .iso https://access.redhat.com/solutions/60959 ^^^ 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 On Behalf Of Jerry Geis Sent: October 4, 2019 11:30 AM To: CentOS mailing list 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 ? Thanks, Jerry ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
