Garmin Nüvi 1490 dead after Firmware Update 6.2 to 6.3

Hi, I just did a firmware update to v6.3 (and the GUPDATE.GCD file was as usual visible in the device).

Now when I try to power up the 1490 I first see the big Word 'Garmin', then the usual 'copyright 2012...' hints... and that's it... screen turns to black/off... I can try as often as possible... always the same behaviour...

Any suggestions?