HP Forums

Can the HP-110 Plus be used to assemble Machine Language for the HP-41? Can this unit be used as a MLDL of sorts?

There was official HP41 ROM development software for generic MS-DOS machines and it would run on the Portable Plus. IIRC, it was called 'SDS-II', and included a user language translator, assembler, linker, ROM image creation programs, etc
It wasn't what I understnad by an MLDL, though (which to me is a piece of hardware). The docs for SDS-II suggested yuo should use a commercially-available ERPOM or RAM box (I think Eramco was mentioned) to test your ROM images before getting
HP to make a custom module for you.