One way to test for that, might be to use a small bit of programming code that reads known-good values back from the DSP. If the chip is dead, those values will be bad.
Mmm.. on further examination, the DSP inside the Mk2a appears to be a
write-only device. I cannot read anything meaningful back from it.
But.. at least it does respond to the I2C read cycles, ACKing when required. If it were dead, it wouldn't do even that. So we now have a test for a functioning DSP.
This
special hijack kernel now performs that test as part of the
Vital Signs display (from the Hijack menu). If the DSP fails to respond, it prefixes the model name with a minus sign.
Eg. if you see this, it's toast:
-Mk2aWhereas this means all okay:
Mk2a-ml