It is actually a problem in the software , i am trying to find a new coder at the present time to resolve this issue.
I found with the 900 i have that if i write the original flash back to the device it programs ok , but the minute i try to flash something different it mismatches.
I am going to try and delete the flash and see if it will program ok that way with no other data present. This is just until i can get someone to look at the code.