Great tool, but I have a few thoughts I wish to share.
1. As for the instructions, I would swap point 1 and 2 as you first need to set the device to Mass Storage before you can remove any gupdate.gcd in the device.
2. Is the FW list in post #1 kept up-to-date and if so, how frequently?
3. Once the device has patched FW, does the device still receive new FW updates via e.g. Garmin Express or WebUpdater? If so, I assume the new FW has to be patched as well?
4. What's the difference between GSV and GVS? I see these terms used mixed.