Nokia N810 (nokia-selene)

This device is closely related to the Nokia N800 (nokia-gagarin), but adds a hardware keyboard and 2GB eMMC instead of a second SD card slot.

Issues
The SoC is very old, just barely new enough to possibly run postmarketOS (ARMv6 with VFP).

The kernel partition is only 2 MB, meaning the kernel will have to be size optimized and modularized as much as possible. I tried to do this, but the resulting kernel does not boot, only hangs at the Nokia splash logo for a minute then shuts down.

Alternatively the kernel could be loaded from another partition, but I don't know how. U-Boot is not supported?

The device only has 128 MB of RAM, which is very limiting and means that most UIs will not run well. Even the original Maemo OS allows you to set up to 128 MB of swap to improve usability. See Low RAM usability.

How to enter flash mode
While connected to USB, hold the two squares button on the left and the power button on the top.