The problem is, the FM stereo comes into the box as one signal - an FM multiplex. This gets expanded into Left & Right inside the DSP.

It's not possible to sample via the DSP - it's a car audio part and not designed to feed a CPU with data. The connection to the main CPU is just an I2C slow serial connection for control.

So, the Mk2 added a sampler on the main CPUs bus. The input of the sampler can be selected from 3 places:

1 - Microphone (for VR)
2 - AUX inputs
3 - Home outputs (this is for sampling the output and doing visuals, eg for the radio)

Problem is, the only way you can record the radio is by playing it.

In theory, you could grab the multiplex and with an external loom, feed it into the aux in - you'd only get mono, unless you used an external FM demultiplexer. Someone could make an external demod box which hooked into the tuner harness and aux inputs and this would then enable the hardware for full tivo-style operation (eg, listen behind, etc).

Hugo