What needs to be done in the following ORDER
1 - Get yourself a firmware (whichever one you want) .42
1.1 - Connect your phone to your computer
2 - Using the application called Flashtool which be can be found on the forum (multiple threads) Flash the the rom. You will loose all your contacts, sms etc...
2.2 - Wait for the tool to tell you that it's done flashing
2.3 - Using ZergRush or Flashtool ROOT your phone.
3 - Start your phone and disconnect it from the PC
4 - Press the menu button and go to SETTINGS - ABOUT PHONE - SOFTWARE UPDATE
5 - This will verify and push the OTA for .62 to your phone.
That's pretty much it in the simplest way possible.
Phone: HTC One - Xperia Z - Galaxy Note 8
Android Revolution HD