What do you mean, not sure
Of Course flashing in General works. Also with your uploader it works:
I Flash the uploader.ino.leonardo.hex from my PC to the arduboy and plug in the arduboy to the RPi and the arduboy recognizes the dock and loads the list of games.
Now i can Flash a game without Problems. But if i want to load back again the uploader by Pluging in the arduboy again to the RPi it does not work just keeps resetting.
When i then plug in the arduboy to my PC and use your loader to load back the uploader.ino.leonardo.hex it also works and i can plug in back the arduboy to the RPi to load another game.
I use Farkle as it seems to be easily to Flash and reflash etc as no tricks are needed and arduboy is recognized directly.
So not sure what i should try on your Website and also to sure if i should try on RPi as there i am just connecting via ssh and would not know how to open a Website via ssh
Edit: just tried flashing a game from your Website on my PC with the link “Flash on my arduboy” and yes, this also works.