are we on about just general updates for individual games? if so i just go ethernet from ps3 to pc, then bridged my local area connection to my wireless network connection, then when the game starts and tells you of available update just accept. i had to do it with my backup of infamous to get english language.
Normal game updates automatically appears and can be downloaded (when you start your game) if your console is connected to the internet.
(This entirely relies on which jailbreak method/payload you are using.
DLC and other stuff usually found in the store, can't be downloaded/activated without connecting to PSN, which needs the latest firmware, 3.50.
Yes all my games download updates like they would normally if I had the real disk , Reason being you dont need to be logged in to PSN for game updates, very handy, the very 1st jailbreak payloads didnt have this feature but its been around for a while, just make sure your jailbreak device is using one of the latest payloads available.
Funnily enough Im just updating the game PAIN online right now, the full game is 1.35GB , game updates are actually bigger I reckon, its already downloaded a 430MB, 405MB, 208MB and now its downloading another 216MB file, WTF!
Just click ok when you start a game and when it says an update is available. Most updates works, some not like just cause 2 update dont work and makeing the game unable to boot, when this happens just delete installed gamedata and install again and try download debug update as mention above with ANUS and if this results in same eroor just remove it again install and dont update, I also first check if a game works without the update, if it does i will update it.
That way you're sure its the update that messed up the game and not the game itself.