no...u still need to jailbreak with software such like iPlus or ziphone...
or else the phone is LOCKED and you cant make call or sms or cant even see the menu screen....

make sure you understand what you are actually doing....
i don't advise others to do it unless it is spoiled or they are confident about their what they are doing....

i was very frustrated to fix it for the whole night....
my advice is "dont try it".

if u wanna try,
u need to know about your firmware version, bootloader,
difference between DFU mode and Recovery mode,
what the is consequence after downgrade the boatloader from 4.6 to 3.9,
and the pro and con for each jailbreak software,
and many things you need to know in and out...

i m not intend to scare u or wan to make it hard......
just that i give u a preparation that u will never know what going to happen next until u do it.....although they are a lot successful upgrade case in youtube or google, so to failure case..

lastly....above the post is just telling how i upgrade my 1.1.2 to 1.1.4,
i can't ensure it will be fine if follow my way, and i am not knowledgeable to give u any better info about flash the firmware...there r risks for upgrade or downgrade

hope u understand about it.