Leo cracked his knuckles. Finding the official driver was the easy part, but the JM40M01 was notoriously finicky with modern Windows architecture. It needed a "repack"—a custom-built installer that stripped away the bloat and forced the legacy ports to communicate with the USB-to-serial adapter.
Ensure the driver matches the printer's ESC/POS mode.
Most JM40M01 units use Serial or USB connections.