You got the Developer Edition HTC One so you could dig in there and really mess stuff up. It's fun, and a good way to learn about how Android works at the nerd level. But after you're done mucking around with things, and need your camera or Bluetooth back, you want to return it to the way is comes out of the box.
Luckily, HTC gives you a pretty easy way to do it. They've posted the 4.3 update ROM for the Developer Edition at their website, and with it you're juts a few clicks away from restoring your phone to a "stock" working condition. Of course, the prior versions are still available should you have a reason to want to go back. Kidding. Never go back.
You'll find them at the HTCdev site linked below(search for Brightstar US WWE) and it's something everyone with a Dev edition M7 should keep handy.
Source: HTCDev
