It sounds to me like you did everything correctly. The image we have posted is a simple binary image so no translation is needed.
First, I'd try putting the original ROM back in and make sure the G2 still works. If it works ok with the original ROM but not yours, double check to be sure you are orienting the chip the right way; make sure the groove is at the same end of the part as the original (not backwards)
Another thing to check is the speed of the part. That's the number at the end of the part number. The parts we have been using are 90ns (nano second) parts: AM29F040-90PC. I just updated the broken link to datasheet on the MPX G2 Parts page: http://www.stecrecords.com/index.php?RecordId=512
. If the checksum is correct but the speed is not 90ns, that might be your problem. See if you can find a 90ns part and try again.