I'm sorry for such a stooped question.. but if I did a factory reset from settings on jb 4.1.2 will it wipe my internal storage ??
If yes how to format only the system without touching internal storage ?
Hmm, i think it's like this.
If you factory reset from
settings, yes the phone will be like the day you bought it.
Although if you "Wipe data/factory set" from Recovery mode, it will only wipe the system storage (where all apps are located) and not touch your internal storage.
So if you want to wipe everything but your internal storage, do it from Recovery mode. If you do this and reboot, you will once again be asked to sign in with your google account etc etc..
Also if you do wipe data/factory set from recovery mode, be sure to wipe cache and dalvik cache, just to be sure you dont have anything left.