22.04 create CDROM

[Jerry Geis]

On Fri, Oct 27, 2023 at 3:41 PM Jerry Geis <jerry.geis at gmail.com> wrote:

>
>
> 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
>

Redownloading the iso, looking closer at the values for start and skip
mentioned in
https://help.ubuntu.com/community/LiveCDCustomization
I was able to get something to work.

Jerry
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