My 9780 had gone crazy and keep rebooting endlessly few days ago. Decided to force update the OS using Method 1 by Ayil (didn't worry about backup coz i backed up my BB periodically). The update process was superbly simple and effective. There's no other way Ayil could have explained it easier in here.

Thumbs up for bro Ayil!

(now waiting for his announcement on the "alien tech" battery for BB that can last for hours or day?)