Yesterday, we published a link to what appeared to be the release version of the iPhone 2.0 Firmware. This version of the firmware was successfully installed on a number of original iPhones and readers were able to start using Apps from the iTunes App Store.

Today, Apple released the official 2.0 Firmware. While it carries the same build number, the file sizes are different and the iPhone model designation is different. One unconfirmed poster explains that the "iPhone1,2" firmware that was leaked yesterday was only intended for use on the iPhone 3G.

The details of the post are up for debate, as the current iPhone 3G will download and use the "leaked" 5a347 firmware upon restore. Still, due to this possibility, we recommend all readers who upgraded to the pre-release firmware to take the time to upgrade to the official firmware. The process is exactly the same. Remember, with any firmware upgrade, there is the possibility that you may lose your data, and we can't take any responsibility.

Before you begin, remember that the phone will have to be reactivated after firmware installation. This normally takes a few seconds when connecting to iTunes, but with the high number of activations today, Apple's iTunes servers have been unresponsive, leaving many waiting to activate. It appears activations have just now started to run smoothly, but you may want to wait even longer before "upgrading" just to be safe.

1. Sync your iPhone with iTunes 7.7 to make sure all data is backed up.
2. Download iPhone1,1_2.0_5A347_Restore.ipsw (Official firmware). You should get a single ".ipsw" file. If your browser renames it to a .zip file, you should rename it to ".ipsw"
3. In iTunes click on the "Check for Updates" while holding the Option key on the Mac (Shift key on Windows)
4. Select the firmware you downloaded in step #2
5. Wait for your iPhone to update and restore.

All your App Store applications and data should be moved over, and all applications should run.

Unrelated to this procedure, there have been sporadic reports of people having Applications quitting immediately after launch. This has happened both with original iPhone and iPhone 3G versions. The solution is to simply delete the application and redownload it from the App Store. Apple allows you to re-download any application for free.

Note: This is not for the iPod Touch. Touch owners need to wait until Apple releases the official Touch 2.0 firmware.

Note 2:: If you never installed the pre-release firmware, you can upgrade to the latest firmware just by clicking on "Check for Updates" in iTunes 7.7. iTunes will take care of the rest...

via macrumors