Yes and software version
Update the software in iTunes and it will do it for you.
Update to the Latest Firmware.
yes. the current update is 3.1.3 and to update to it you have to restore you iphone, update it then re-jailbreak it. but at this moment in time this is not an jailbreak for firmware 3.1.3.
Upgrading an iPhone will update the firmware (the iOS) and will therefore remove the jailbreak. If you wish to stay jailbroken, it is highly recommended to not update until news of a new jailbreak arrives for the upgrade.
Not sure. Why not downgrade?
No. Linux cannot overwrite iPhone's firmware, as it is encrypted. Only iTunes can do that.
Home/Menu > Settings/Tools > Update Phone (Option 8) > Update Firmware (Option 1). Hope that helped.
no
It does it it self.
Samsung has stop producing P2 and the latest firmware update is 5.10. No more updating, I suppose.
Firmware update 2.70 released today next update may
No. You must restore to Downgrade the Firmware!