Extra kernel features are much easier to obtain on the Nokia N900 than the N810 because of the provided kernel-power packages. The kernel-power some special trickery required to obtain this special kernel and retain camera functionality for BlessN900 (or FCamera) because the stock camera software takes such poor pictures.
What happens here is that the kernel-power, kernel-power-flasher, blessn900, and the required fcam-drivers packages are installed from the extras-devel repository instead of the standard extras repository.
In short, the following versions seem to work:
Here are slightly more verbose instructions:
Start with the stock kernel, and blessn900, fcamera, and fcam-drivers packages uninstalled.
Enable extras-devel repository
Application manager / application catalogs (tap title bar) / New
Name = extras-devel
Web address = http://repository.maemo.org/extras-devel
Distribution = fremantle
Components = free non-free
Save and wait for catalog updating
Open a terminal; close all other applications
Install the kernel-power package from the application manager
Disable the extras-devel catalog
Install blessn900 using this package: