I haven't with a MB1 but it will no doubt be the same/similar to the MP1 (which I have done), you have to connect the MB1 MIDI In & Out to the MIDI interface of a computer and the computer writes/reads the file(s) to a drive (it's just a SYSEX file dump albeit an important one
). The older style PC sound cards had MIDI in/out DIN sockets you could connect to, some digital I/O interfaces also have them (e.g. Digi 001/002). You can also get USB to MIDI DIN adapters. Basically to get the SYSEX dumps from/to (you can load them also) the MB1 the connection is via the MIDI In/Out DIN sockets to a PC or device that supports MIDI SYSEX.
But specific MB1 stuff is more Peter territory, I'm sure he's done this with his MB1s and can help you sort it out