via Scott Metzger on the AH list:
"This makes me very happy. Haven't had a chance to check it, but it supposely fixes the detune issue when spinning the input knob quickly. This is a huge deal!!!
Moog Source SMK MIDI Retrofit Version 4.10 This version of the SMK fixes a few bugs and incorporates a new installation procedure.
In previous revisions, if the Incremental Controller was turned too quickly, the sample and hold update code would fall behind and the voice would temporarily drift downward. This was due to a sharing of the Z80 interrupt line. Version 4.10 uses the NMI line for MIDI, and the INT line for the Incremental Controller, alleviating the problem.
Fixed a sysex load problem.
Fixed a minor bug with Level 2 – 5 waiting for the old PPQ parameter.
(Note: This firmware revision (and all following revisions) require a modification to the installation.)
http://www.encoreelectronics.com/sour410.zip"