i have a new 3GS with 4.3.3 ... when i jailbreak it now with jailbreakMe, is it possible to restore it with the original firmware (4.3.3) later or make jailbreakMe a basband update or something other so that i can't restore it withe the original firmware.
I am pretty sure if you have your SHSH blobs either on saurik's cydia server or on your local machine with tinyumbrella you can always downgrade firmwares, but that gets more complicated if you have to preserve your baseband for unlocking purposes. I am still on 4.3.2 on iphone4. BB 4.10.1. I want to unlock now to sell this device so I'm waiting patiently.
The only reason why you would ever be restricted and not be able to use a stock firmware is if you manually use sn0wbreeze/pwnagetool/redsn0w to upgrade your baseband to the iPad baseband. If you don't authorize it with any of the above mentioned tools, the baseband can't be upgraded to 6.15.00, restricting restores to stock firmware on 4.2.1+.
Using jailbreakme does not upgrade the baseband to the iPad bb, therefor does not restrict you from restoring or updating to stock fw.