explain the use for all the tools

Nobody has claimed this yet.

There are many tools involved. Those to build and rework firmware images, those that would be contained in the images, those that may be companions on the development machine when debugging a target, etc..

## Debugging

- platform state investigation (`dmesg,`, checking on interrupts, etc)
- interactive debugging, e.g. MSR writes/reads, memory writes/reads, etc
- do we have tools like [U-Boot's `md`](https://docs.u-boot.org/en/v2024.07/usage/cmd/md.html) etc?
- zero cost vs proprietary hardware debuggers that are no accessible to most people
- [kgdb](https://www.kernel.org/doc/html/v4.14/dev-tools/kgdb.html), very valuable, but hard to set up

## Image building/reworking

We have a whole chapter on utk, and that is merely UEFI.
There are dozens of platforms that need other tools.
See also https://github.com/platform-system-interface

## Building a rootfs, possibly a DTB and a kernel

While straightforward to a degree, the devil is in the details:

- compression may need support in firmware where Linux builds a non-self-extracting `Image`(`.gz` etc)
- U-Boot SPL supports FIT (.itb), needs guidance
- different OSes need different loaders (e.g., FreeBSD; see the work Warner Losh did)
- it may be necessary to split kernel and initrd vs the possibility to embed the rootfs as initramfs

Start by reviewing the existing utk chapter and the issue’s Debugging, Image building/reworking, and rootfs/DTB/kernel sections. Consult the linked U-Boot md and kgdb documentation, plus the platform-system-interface reference, to define the tools and guidance needed; done means the book explains the relevant tool categories and image-building details.

Written by the indexing model from the issue text.