Running Motronic 55 pin conversion on one S2 with distributor and another with COP (both 3B engines). 1.1.44 has worked well on both.
Figured I'd try 1.1.54, but the tables for spark and lambda got messed up in VemsTune every time the VEMS had been turned off.
In case anyone else has the same probs, just edit the VemsTune INI-file:
Search for "page 3". The table definition array for lambda has 2 entries that look like this: [8X8] - replace the uppercase X with a lowercase x.
Search for "page 4". The table definition array for spark has 1 entry that looks like this: [12X12] - replace the uppercase X with a lowercase x.
This did it for me.
If your OS moans about editing rights, uninstall VemsTune and install it again outside the "Programs" folder or in an entirely different partition.