MMWAVEICBOOST: Rev A PROC074A not flashing isk

Hi,

I have two mmwaveicboost boost boards, with the two IWR6843ISK's. 

One with PROC074B PCB silk screen label that works.

And one with PROC074A that doesn't seem to work and doesn't flash the isk. 

All the switches seem to be right and sop 2 set to flashing mode, so unsure what is wrong.

Looking at the design files here

can only see Rev A and not Rev B, what are the differences?

And would the differences explain why it may not be flashing isk's with Rev A but Rev B mmwaveicboost

Or could this be an SDK requirment? 

Thanks in advance

Calex