OnePlus One Recovery Mode

  1. With the device powered down, hold the Volume Down and Power buttons.

OnePlus One Fastboot Mode

  1. With the device powered down, hold the Volume Up and Power buttons.

OnePlus One Developer Mode

  1. Switch it on going into the Settings Menu
  2. Scroll all the way to "About Phone"
  3. Tap the "Build Number" 7 times
  4. Once unlocked you will see a new "Developers Options" menu within settings