Got it running:

Here’s what you have to do:
-
Update your OS to the testing release. This won’t be required in the future, but for now the ability to run a custom program after bootup isn’t available in
stableyet. -
Fetch this hyperpixel zip
-
Extract the zip file onto the SD card, so that userconfig.txt ends up in
/configon the SD -
Start he Pi
The settings from the HyperPixel repository by default rotate the screen, so it’s horizontal with 800x480 resolution. As this rotation puts extra load on the GPU, it’s a bit slower than it could be. You can avoid this rotation (and get 480x800, like you see in the picture above) if you take a look at /config/userconfig.txt and comment out the three marked lines.