If your device does not update, which you can best recognize by the fact that the software version does not change after the update, please proceed as follows:
- Try one or more other USB sticks. Preferably "old" USB sticks with little memory (e.g. 4GB).
Repeat the update attempt several times: Some AT-, especially early serial numbers, recognize USB sticks for the update only after several attempts.
- Make sure that the update file has not been modified by your operating system or corrupted during the download by downloading a file on another PC and playing it on the USB stick.