Same problem after purchasing the device and updating via Line6 Updater - what is afaik in most cases not necessary. This description of a working fix helped me a lot and kept me from returning the FBV3 to my dealer. Alas, the description is hard to find for German users, so I'd like to repeat:
FBV3 zurücksetzen auf Werkseinstellung (FBV3 reset to factory defaults): press FS1 and A simultaneously, then connect USB-Cable. Device will display "In Update Mode", the update itself will complete within less than a minute.