This page documents various hacks I did on my N810. I will not assist you with repeating any of these hacks.
Install libltdl3 from
deb http://jalimo.evolvis.org/repository/maemo/ maemo4.0 user
and these two debs (must be installed manually, application manager doesn't like them): https://johannes.sipsolutions.net/files/libgphoto2.deb https://johannes.sipsolutions.net/files/gphoto2.deb
Grab any of the USB mode switchers and switch to host mode.
I have also removed all but the ptp2 module after installing the deb there so gphoto2 is a lot quicker to start up.
Unfortunately, the N810 crashes when this is used, at least it does for me. Serial console (see below) didn't show anything.
Michael has instructions and a diagram. Just be careful, he labelled a pad "RxD", that is where you have to connect the RX wire of your serial converter, it's where the N810 sends. And GND may be mislabelled too, just connect to the minus (-) pad of the power pads.
Building crypto modules
mac80211 and some other components need a kernel compiled with CONFIG_CRYPTO. The default N810 kernel isn't compiled with that option so this introduces a hack that allows you to build crypto as modules. That's obviously unsupported but works :)
Firstly, you need this patch: https://johannes.sipsolutions.net/patches/n810-modular-crypto.patch
It allows building crypto modules while the base kernel thinks crypto is unavailable.
Then, simply configure everything in the crypto menu as modules. Bingo :)
For the lazy people, here are prebuilt modules.
Building new wireless code
The linuxwireless.org site has compatibility code for older kernels at the download section. Follow their directions, I will not assist you.
Note that there is no driver for the built-in wireless yet, but you can of course hook up any of the supported USB devices if you put your N810 into host mode.
In order to make p54spi work, we need to figure out what the upper MAC (umac) does with the chip. Here's a log made with a modified cx3110x wireless driver that logged all SPI transfers. The format is always
[timestamp] (PIO|DMA)(RD|WR) <hexadecimal data>
Hopefully I can try to make the PHASER devices work with p54common using this data...
See my p54 notes for more on that.