So moistgun helped me with that same issue when using TGK. You have to put the board in bootloader, then launch the exe in the tool folder called zadig. Go to options, show all devices. Then choose this option
Show Image
Then you do the setup.bat file
choose
2
N
1
1
then drag your keymap.eep file onto the reflash.bat file and follow directions
That got the tkg tool to work but flashing the .eep file generated by the tmk keymap generator bricked a few keys. I may be using a wrong build or something.
Things that I have tried after tkg starting working:
1. Flashing keymap.eep - debounce time got weird and couldn't type v, u or space and some other letters
2. Flashing the original .hex from the tkg repository, then flashing keymap.eep - the original .hex works but the keymap.eep does not!
3. Built the gh60 firmware on linux from tmk and tried flashing that using tkg same issue as number 1
Maybe I got a weird version of the pcb. I'm perfectly happy using easyAVR's keymap as my firmware but the only thing I'd like are for my LED modes to work.