QUOTE(GrandElf @ Feb 20 2013, 11:50 AM)
oppss..sry for using the wrong word..yes, I mean I want to try factory reset.....factory reset will restore back my phone to the oldest firmware (means 1st firmware when I get my phone) right? after that will need to update again to jellybean, correct?
@ivanchingkl
what you mean by wipe cache partition? any guides on this?

Factory reset will erase all data but remain the firmware version.
E.g. if u r in version 4.1.2 now, after factory reset will remain 4.1.2, no more upgrade
Wipe cache partition will erase cache only without affect ur data/apps in your phone
1. shut off ur phone
2. pressing power + volume up + home button
3. choose wipe cache partition (by using volume up down key, power button to select)
4. choose restart
This post has been edited by ivanchingkl: Feb 20 2013, 11:59 AM