Thanks very much for the continuing updates. The binary runs fine on my original Ormerod Duet.
I normally do a source compile on a Linux machine and noticed a couple of things with this source.
There are two instances where the source code is including a file but the case name of the file does not match any more. This doesn't affect WIndows compiles but causes errors on Linux systems where case sensitivity is obeyed.
The first case is that MassStorage.h refers to "Libraries/FatFs/ff.h" but the directory is Fatfs
The second instance is that the Reprap.h file is referenced as RepRap.h in multiple places
I changed these with a global edit and then it compiled fine under Linux and produced a binary identical file to that in the release.
As far as I can see the case sensitivity got introduced around Christmas day.