If you've inadvertently reprogrammed the firmware in your DM126D drive
this is the firmware to return it back to 1.7B

Please note that other drives were used in the 528 machine
please do not use this firmware to reprogram them - they will stop working.

1.7B firmware as used in the DM126D

Instruction file

Please note I haven't tested this firmware myself but it is from a reliable source