Ok - I *think* I get it. There is the bootloader and operating system (which I have loaded), then there are applications like the Midibox64, Midibox64e, etc like this one (latest?)
zipfile: midibox64_v2_4f.zip midibox64_v2_4f\setup_midibox64.hex <--- is this the right file to upload?
then a setupfile (bank?) like
zipfile: midibox64_v2_4f.zip midibox64_v2_4f\tools\mk_syx\midibox64_generic.syx -OR- the output from Serge's wonderful Midibox64 configurator.
Is the above right?