Teensylu boards often ship with LUFA CDC pre-installed from China. While this is nice we still need to upload a firmware to the board. Unfortunately this is not as easy as Pi and using a modded Arduino IDE is necessary. This is because the board has an AT90USB1286 chip which has an USB converted integrated and for some reason is not officially supported by Arduino. I found some instruction on the reprap wiki and a blog but they did not work for me. What I don’t like about the wiki page is that it describes the procedure of uploading with lots of additional tools which are totally not necessary. Rubbish I say. Edited it already but the changes are awaiting moderation or some kind of anti-anarchy-precaution-system-ish thing. To hell with it, I’ll post my findings here.