Add support of IMG format

[vitaly-zdanevich]

This script handle ISOs, but not IMG.

Previous issue was strangely closed by @zeha saying that

Please find some support forum and ask there.

Ask what? I already tested - this software does not handle IMG images.

I'll finally note that Grml releases are provided as ISOs, and not as "IMG" (whatever that might be).

"whatever that might be" - please read https://en.wikipedia.org/wiki/IMG_(file_format), and as it was mentioned in the original issue - you can find an example here https://github.com/debootdevs/deboot/releases/tag/0.2.0
and
https://cdimage.ubuntu.com/releases/jammy/release

Grml can be provided in ISO or another form, this issue is about be able to boot an IMG.

[mika]

Grml can be provided in ISO or another form, this issue is about be able to boot an IMG.

You seem to be misunderstanding what grml-rescueboot is about.

Quoting from https://github.com/grml/grml-rescueboot/tree/master/debian:

Usually systems are rescued with CD or USB stick. grml-rescueboot makes
it possible to simply copy an Grml ISO image to the harddisk and boot the
rescue image. This eliminates the need to carry around a USB stick
to rescue a system as long as the hard disk and the boot manager still
work.

grml-rescueboot includes the script 42_grml which is installed in
/etc/grub.d and run when update-grub is executed. The script looks for
ISO images in /boot/grml/ and adds an entry for each image found.

We care about our Grml ISO files (which are also dd-able to devices).

We (as in the Grml project where you're reporting your issue) don't have nor provide any img files .

I also don't know whether such a Ubuntu img file could even be loaded by GRUB and whether those Ubuntu or deboot img files include the GRUB loopback.cfg configuration file (see https://supergrubdisk.org/wiki/Loopback.cfg) which is essential for booting via grml-rescueboot / GRUB.

Put in other words: 1) you need to figure out whether GRUB supports booting / chainloading img files, 2) those img files provide the loopback.cfg configuration file. If both are given, we could technically add support for those within grml-rescueboot.

[vitaly-zdanevich]

1. you need to figure out whether GRUB supports booting / chainloading img files,

I was able to dd boot.img to USB and boot from it

[vitaly-zdanevich]

2. those img files provide the loopback.cfg configuration file.

According to my research, the same as with ISO - loopback.cfg may or may not be present.

[vitaly-zdanevich]

Another project that provides not ISO but IMG https://tails.net/install/download/index.en.html

[vitaly-zdanevich]

Just for your information - useful property of IMG - it can be writable, ISO is read-only.

[zeha]

Non-Grml is probably better served by grub-rescueboot

[vitaly-zdanevich]

On Wikipedia I see

ISO images are another type of optical disc image files, which commonly use the .iso file extension, but sometimes use the .img file extension as well

[vitaly-zdanevich]

Non-Grml is probably better served by grub-rescueboot

Is it a project?

[zeha]

https://tracker.debian.org/pkg/grub-imageboot

[vitaly-zdanevich]

Like with this project - I can have multiple local images in grub?