I’ve received the error message ‘Fatal: Not supported, on operation start DFU update’

If this happens, your doppel is stuck in ‘DFU bootloader mode’ - usually as a result of a failed firmware update or reset.

If the update did not complete, you might notice that your doppel’s touch controls are unresponsive, or that it doesn’t buzz when you put it on the charging base. Don’t worry, if this happens it's because your doppel is now stuck in 'DFU bootloader mode' -  it's essentially sitting in a state where it's waiting for information.

How do I resolve this?

If this happens, first close the app, then open it again and try and scan for your doppel on the My doppel page. The app should find your doppel. Once paired, navigate to My settings and run the firmware update/reset again. This should solve the problem, if not please try the same steps by force quitting the app.

How do I force quit the app?

If you are using an iPhone double click the home button, all of your apps will display in a deck format, swipe up over the doppel app to force quit. If you have the iPhone X, simply hold your home "button" for a few seconds and when the deck of apps appears on screen click the red icon at the top left corner of the doppel app to force quit.

If you are using an Android phone, launch your recent applications menu, scroll to find the doppel app, then swipe right to force close the app.

I've followed these steps but nothing has improved

If this doesn't work, or the firmware update keeps failing, please contact the customer support team including the following information:

1. Your mobile phone make and model
2. The operating system you are running (e.g iOS.12)
3. Whether doppel appears in your Bluetooth settings list as "doppel" or "DFUtarg"

This information is important and will help us efficiently solve your problem.