Recording works now, although I'm sure there will be a few
things that need fine-tuning. A major issue is that writing
to the SD card creates noticable interference, which happens
on the original firmware too but seems worse under Rockbox.
(Since Rockbox waits until RAM fills up before writing data,
the interference will only be heard on >50 MiB recordings.)
Change-Id: I5561dd9668c3bdd34e92f34ef50848aef8c0b7eb
Includes installation instructions and a description of Rockbox's
limitations versus the original firmware. Some things are still
missing, notably screenshots for the Q1. The M3K image also needs
to be updated to include the 'select' button.
Change-Id: Ib533206df01925203edeccdd75e1bf22f407e794