22.04 create CDROM

[Jerry Geis]

On Fri, Oct 27, 2023 at 2:04 PM Jerry Geis <jerry.geis at gmail.com> wrote:

> Seems the command to re-do the CDROM on 22.04 is different than on 20.04
>
> I found this:
>
> https://askubuntu.com/questions/1403546/ubuntu-22-04-build-iso-both-mbr-and-efi
>
> The command they say to run:
> dd
> if=/home/silentm/CDROM.iso/Ubuntu.22.04/ubuntu-22.04.3-live-server-amd64.iso
> bs=512 skip=7129428 count=8496 of=/tmp/efi.img
> dd:
> ‘/home/silentm/CDROM.iso/Ubuntu.22.04/ubuntu-22.04.3-live-server-amd64.iso’:
> cannot skip to specified offset
>
> Gives an error - cannot skip to offset.
>
> Has anyone made a customer CDROM for 22.04 ? how ???
>
> All I'm trying to do is change the grub menu.
>
> Thank you
>
> Jerry
>


This page: https://help.ubuntu.com/community/LiveCDCustomization
Uses the DESKTOP disk - I am using the server disk

 sudo fdisk -l ubuntu-22.04.1-desktop-amd64.iso
This will yield significant information including the offset and size of
the EFI partition. For example -

ubuntu-22.04.1-desktop-amd64.iso1      64 5465119 7465056  4.1M Microsoft
basic
ubuntu-22.04.1-desktop-amd64.iso2 7465120 7473615    8496  4.1M EFI System
ubuntu-22.04.1-desktop-amd64.iso3 7473616 7474215     600  4.1M Microsoft
basic

There example is above, muy server disk is:
fdisk -l ubuntu-22.04.3-live-server-amd64.iso
WARNING: fdisk GPT support is currently new, and therefore in an
experimental phase. Use at your own discretion.

Disk ubuntu-22.04.3-live-server-amd64.iso: 2133 MB, 2133391360 bytes,
4166780 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: gpt
Disk identifier: F19CB4F2-831A-42FA-B510-0DD91B961BBF


#         Start          End    Size  Type            Name
 1           64      4156047      2G  Microsoft basic ISO9660
 2      4156048      4166115    4.9M  EFI System      Appended2
 3      4166116      4166715    300K  Microsoft basic Gap1


Does not even look the same ?
I am trying to get the skip values for the EFI
7473615    8496  4.1M EFI System (for the example)

my server disk does not look the same.

I am confused. What am I missing?

Jerry
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