To update the TOTP authenticator you need the following:

* A authenticator with the dfu bootloader installed (prebuild bootloader can be found here.

* Dfu util

* New software

To install the new firmware follow the following steps:

1. Hold the "enter" (the center) button and plug the authenticator into your pc. The screen should stay blank and the light on the bottom side should light up.

2. Open a terminal

3. Run dfu-util with parameter "-D" with the file to download to the device.

4. Unplug and plug the authenticator in your pc to start the new software.