What toolhead offset issue? MBI changed the dualstrusion system in RepG 40 from what existed in RepG 39 and earlier. There's nothing to "fix" there per se. You either use the old system or the new system. However, the currently released versions of Sailfish do not support the new system. The next release -- 4.2 & 7.1 -- will support both the old and new dualstrusion systems. That release is due out this upcoming week.
If, however, you are referring to some other issue with toolhead offsets, then please be more specific. And, more importantly, please discuss on the jetty-firmware mailing list.