I don't think you'll find that anywhere, at least not for the MSD80 and MSD81. Some tools exist for other DMEs. NCS dummy can correct the checksums, but correctly signing the 0pa file so that it passes RSA verification is the tricky part.
If you know C#, there are open source flashing projects that could be adapted to the MSD80/MSD81. They bypass RSA verification by modifying the boot loader and allow you to read the entire memory contents which is not reflected in a 0pa alone.