backup COBB flash with BBflash ?

Is it possible to backup the COBB flash using the BBflash tool an then restore it on the car when it is unmarried with the cobb?

Did a full read yesterday, but at the end the BBflash says file not valid, avoid write it. maybe not valid because it is different then the BMW rom as it is a COBB rom?

Is it a big risk to write the file to ECU? will I brick it?