Mate you need to BACKUP youre activation before you update And jailbbreak here is the procedure for Backing up and Restoring Youre Sam activation ticket.....
How to Take Backup of Activation Ticket After Unlocking Your iPhone Using SAM Backup method
http://www.ijailbreak.com/how-to/res...sn0w-0-9-12b1/ Restoing sam Backup ticket method.....
BR...
Tabbu khan