The GPL (and other FOSS) sources from Archos have been checked into git for convenient patching and access:
(You will need only one of both kernels checked out into the gen9 buildroot)
Howto build a mini sde image from the source can be read here http://gitorious.org/archos/archos-gpl-gen9/blobs/master/Readme_SDE.txt
A list of Linux distributions to run on Gen9
- Mer with KDE PlasmaActive?
Archos provides two kernel trees. One is from their Android Honeycomb firmware, the other is the base for their Android IceCreamSandwich. Generally the latter should be preferred as it's based on a newer upstream kernel. Added on top of upstream are TI patches (a lot) and Archos specific hardware patches (some).
Index of gen9 wiki pages:
Note: This will list all pages with Gen9 as prefix.