TANONE  Thank you... same here with a Firewire/USB 250 GB Little Disk (just 1 week old!!!). The firmware update stopped at 83% and I was completely unable to recover the drive until I followed your advice: selected the Mobile model and I got it back to life, without any data loss. The important thing to comment is that this happened with the latest version of the LaCie Update Tool (2.0). I also used this version to update two other LaCie drives (a Rugged 80 GB and a desktop Porsche 320 GB) without any problem.  
(Version 2.0)