Siemens C7-633 won't work with memory cards- drops off network

The situation is we have a C7-633 –part 6ES7 633-2BF02-0AES which appears to work fine when we don’t try to use a memory card which I’ve programmed ok with the HMI part on MPI 1 and CPU on MPI 2.
However If I boot with a blank memory card in the slot the CPU drops off the MPI network and I can only see the HMI. The HMI ends on this error - $551 AS address 2 not possible.
If I use our Field PG to program the card with the same program and then insert it into the device the same thing occurs.
If I power the device without memory card and download the program then insert the memory card. The option to Download to memory card becomes available but this doesn’t appear to do anything apart from causing the same error.
The problem is only whenever I try to use a memory card with our c7-633. I have two which I’ve been trying a 64k 700-951-0kf00 and a 256k 6ES7 951 1KH00-0AA0. Both look to be working in field PG one I know is good as I’ve used this year on another job and PLC.

I suspect I have a faulty unit which does not work with memory cards.