
Via the developer, Amedeo Farello: "I have just completed version 2.1 of
GI20Editor, a software editor for the Roland GI-20 GK-MIDI guitar interface.
Besides being the only alternative to programming the device through a knob, a two digit display and a few buttons, GI20Editor can greatly enhance the guitar/synthesizer connection experienced through the GI-20.

New in version 2.1 is the possibility for each patch to send up to 8 user defined MIDI Control Change messages for each string/channel to the 'synthesizer output' device.
GI20Editor is available now in the
Mac App Store at $13.99." [Version 1.5 for Windows is available
here]

Description from the App Store:
"GI20Editor is a software editor for the Roland GI-20 GK-MIDI guitar interface.
Besides being the only alternative to programming the device through a knob, a two digit display and a few buttons, GI20Editor can greatly enhance the guitar/synthesizer connection experienced through the GI-20.

A detailed manual and a demo version are available [
here]
Features:
• clear and easy access to all the GI-20 parameters
• save complete GI-20 setups as documents, for backup purposes and fast switching between different configurations
• import and export of GI-20 dump files
• patch related copy, paste and swap commands, plus a powerful 'paste special' function to apply only selected changes, possibly extending them to all patches at once
• direct connection to a MIDI synthesizer

• on-the-fly substitution of GI-20 bank/program messages to allow rapid testing of different sounds without the need of a “bulk load”
• optional MIDI system exclusive, bank/program change and control change messages sent at patch selection
• string grouping options for faster editing
• MIDI remote control"