Upgraded to 1.01.17, now stuck at 480p

My WD TV Live worked rather fine under the original firmware (1.01.10). As there were I few minor bugs, I upgraded it to 1.01.17 : now, the signal is stuck at 480p, whereas before I got 1080p.

Does anyone have the same problem, and possibly a solution ?

BTW I use HDMI to a Full HD Sony TV.

Answer to self : the problem got away by simply unplugging and replugging the HDMI cable. I first tried to reboot the WD Live, but it wasn’t enough.