The recent announcement of iPhone OS 4.0 beta brought some interested features for developers. I’m still pretty new to iPhone development and was trying to figure out how to update my phone. Below are the instructions once you’ve downloaded the IPSW file to update the firmware.

Installing iPhone 4.0 beta on the iPhone

1. Make sure to have downloaded the iPhone 4.0 beta firmware that relates to your iPhone (e.g. 3GS).
2. Extract the firmware IPSW to a folder.
3. Connect the iPhone to your computer.
4. Get the UDID registered on the iPhone Developer program. Provisioning Portal > Devices > Add Devices
   
5. Open iTunes and click Restore while holding the Shift key (for Windows) or Option key (for Mac).
6. Locate or browse to the firmware IPSW.
7. Wait for iTunes to unpackage and install the firmware.

UDID can be view in 2 ways:

1. In Xcode, navigate to the ‘Window’ drop down menu and select
   ‘Organizer’. The 40 hex character string in the Identifier field is your
   device’s UDID.
2. OR In iTunes, select your device in the ‘Devices’ section and navigate to
   the Summary tab. Click on the Serial Number label to reveal the
   Identifier field and the 40 character UDID. Press Command+C to copy the
   UDID to your clipboard.