[jacquesm]

Sounds like it is time to buy a printer, rip it apart and document the firmware after reverse assembling it.

[davelnewton]

"Reverse assembling" == "disassembling"

[jacquesm]

Reverse engineer, apologies. The idea is to gain understanding, not simply to get a disassembly (that's an automated process and a 1:1 correspondence between binary and assembly code remains).

The harder part is to figure out what it all does.