To my knowledge, the electronics didn't change between MK3 and MK4,
only the laser-cut parts to address the failures people were seeing.
Download ReplicatorG 0008 and install the firmware included with it.
Aside: I'm still using skeinforge bundled with ReplicatorG 0005.
Haven't managed to tweak latest-skeinforge to produce nice results.
Andrew.
--
"The future is already here. It's just not very evenly distributed"
-- William Gibson