just in case somebody wants to make experiments with changed grub.cfg,
here are instructions how to create a modified ISO from an Ubuntu amd64
original (but not from a "powerpc" ISO):
Set paths to the original ISO image and for the emerging ISO image:
This run of xorriso will issue some righteous warnings
xorriso : WARNING : -volid text problematic as automatic mount point name
xorriso : WARNING : -volid text does not comply to ISO 9660 / ECMA 119 rules
because of the blanks and lower case characters in
Volume id : 'Ubuntu 21.04 amd64'
It will analyze "$ORIG" for boot equipment and boot entry points in order to
create the same in "$NEW"
xorriso : NOTE : Replayed 22 boot related commands
xorriso : NOTE : Copying to System Area: 32768 bytes from file '--interval:imported_iso:0s-15s:zero_mbrpt,zero_gpt:ubuntu-21.04-desktop-amd64.iso'
Then it begins to write to "$NEW" an ISO image of roughly the same size as
the size of "$ORIG". Enjoy the progress messages. :))
When done, put "$NEW" onto the USB stick and try what happens.
(Maybe mount "$NEW" and check whether your changes really did get into
effect in /boot/grub/grub.cfg, before the lengthy dd to USB stick.)
Hi,
just in case somebody wants to make experiments with changed grub.cfg,
here are instructions how to create a modified ISO from an Ubuntu amd64
original (but not from a "powerpc" ISO):
Set paths to the original ISO image and for the emerging ISO image:
ORIG= ubuntu- 21.04-desktop- amd64.iso 21.04-test. iso
NEW=ubuntu-
Extract grub.cfg from the original ISO to the current working directory:
xorriso -indev "$ORIG" -osirrox on -extract /boot/grub/grub.cfg ./grub.cfg
Make the extracted file writable:
chmod u+w ./grub.cfg
Now edit the file.
My proposal is to remove the 5 lines about grub_platform.
Make sure that a file with path "$NEW" does not yet exist.
Then create the new modified ISO:
xorriso -indev "$ORIG" \
-boot_ image any replay
-outdev "$NEW" \
-map ./grub.cfg /boot/grub/grub.cfg \
This run of xorriso will issue some righteous warnings imported_ iso:0s- 15s:zero_ mbrpt,zero_ gpt:ubuntu- 21.04-desktop- amd64.iso'
xorriso : WARNING : -volid text problematic as automatic mount point name
xorriso : WARNING : -volid text does not comply to ISO 9660 / ECMA 119 rules
because of the blanks and lower case characters in
Volume id : 'Ubuntu 21.04 amd64'
It will analyze "$ORIG" for boot equipment and boot entry points in order to
create the same in "$NEW"
xorriso : NOTE : Replayed 22 boot related commands
xorriso : NOTE : Copying to System Area: 32768 bytes from file '--interval:
Then it begins to write to "$NEW" an ISO image of roughly the same size as
the size of "$ORIG". Enjoy the progress messages. :))
When done, put "$NEW" onto the USB stick and try what happens. grub.cfg, before the lengthy dd to USB stick.)
(Maybe mount "$NEW" and check whether your changes really did get into
effect in /boot/grub/
Have a nice day :)
Thomas