The G304K doesn't have dedicated buttons, touchscreen only.
I have a G306A that I got stuck in a constant reboot cycle, but after about the third time it rebooted, it detected it had a bad application and went to a firmware update screen. So, I was able to Undo a few steps in my Crimson 3.0 software to remove the bad code I had put into the thing, and then perform a download and get it going again.
I would suggest creating a simple dummy application and perform a download, and hopefully it will download the firmware and all, and get you going.
If you can't unbrick it, get ahold of the Red Lion guys. They will probably want you to email them a copy of the application that caused the problem, and may be able to guide you to a solution over the phone.