It appears the Apple TV kernel is not just a kernel itself. It’s holding a lot more.
It is compressed with an odd compression algorithm “complzss”.

After decompressing this file, you’ll notice it contains multiple file headers!
After cutting the file, there are approximatively 100 resulting files.
But without names. Those files are prolly the missing kexts, daemons, etc…

Read a tutorial from semthex on how to extract the kernel here
Join hacking force here

Apple TV has been hacked to play anything like divx, xvid, …
A modded Apple TV HD image is floating around on some torrent site.

“This is a slightly-modded AppleTV dmg file of all three partitions,
for use when you screw up your own modding – you can restore to this one.
It has a startup script disabling the firewall, with ARD and sshd running.
(ssh -1 frontrow@your.appletv.ip, password frontrow). It’s pre-set for 720p.”

The other interesting thing is that Apple TV runs on common hardware Pentium M,
Intel 945G, Geforce Go 7300. And it might run some form of OS X (possibly 10.5).

Update: The image appears to be a modded 10.4.7 with some of the 10.4.9 kexts.

Upgrade your Apple TV hardrive for a bigger one here