First of all, thank you for describing the tool.
I have some questions.
1) As my GPSMAP64s has no touch screen, I didn't find how to go into MTP-mode. Any suggestion found in Google. On the W7-PC I made visible hidden and system files and didn't see "gupdate.gcd". To be sure, I created a dummy gupdate.gcd and copied into the root of the GPS: no overwrite popup, dummy deleted.
If someone can tell how to activate MTP-mode with no-touch-screen-Garmin's?
2) In the file "HWID numbers.txt", there is no GPSMAP 64s. As workaround I did a google on "GPSMAP64_WebUpdater__430.gcd", Google found a link, I could download the 10MB file.
hint: if Garmin promotes in a few months update 4.40, just google for "GPSMAP64_WebUpdater__440.gcd"
3) For the updater procedure, I wasn't able to find a workaround. As described, I dragged the patched rgn file into updater, select USB and plugged the GPS in the USB. As there is no touch screen, I let start the GPS till the GPS is seen in Windows Explorer.
Pressing OK returns the popup: "There are no USB devices connected". Tried several times. Someone has a suggestion?