Just realized how to use 1ddtool.exe with SMC-777 (and use these images with the emulator too) smile

Basically, you need the "Develop 1.4" (that is actually the filer) loaded into drive A: and the "custom image" inside drive B:

[Linked Image from mamedev.emulab.it]

[Linked Image from mamedev.emulab.it]

[Linked Image from mamedev.emulab.it]