Apple released the iPhone OS 4.0 Beta recently and we have already covered about “New Features in Apple iPhone OS 4.0 – Multitasking, Folders, Mail, iBooks, Enterprise, Game Center and iAd“, “Direct Download Links of iPhone OS 4.0 8a230m Build For iPhone 3GS and 3G, iPod Touch 3G and 2G“, “Procedure To Jailbreak iPhone 3G on 4.0 Firmware With Redsn0w 0.9.5” and “How to Unlock iPhone 3G on 4.0 Firmware Using Ultrasn0w“. Though it is not recommended for normal users to upgrade to iPhone OS 4.0 as the 4.0 Firmware Jailbreak is very buggy. Moreover if you rely on an Unlock, upgrading to iPhone 4.0 Firmware will update the baseband to 15.13.03 and you will loose your unlock.

If you have have got an iPhone 3G and upgraded to the latest iPhone OS 4.0, you can jailbreak it using Redsn0w 0.9.5 and enjoy some of the new features like multitasking and homescreen wallpapers.

Procedure to Enable Wallpapers on iPhone 3G and iPod Touch 2G on iPhone OS 4.0

• Once you are done with Jailbreaking, install “OpenSSH” from Cydia.
• Now connect your iPhone to the computer and SSH to your device.
  • Download any FTP program like WinSCP, Cyberduck or FileZilla.
  • Enter the IP address of your iPhone in ther Server field.
  • Give the username as “root” and password as “alpine” (If you haven’t chnaged it!)
  • Select or enter the protocol as SFTP.
• Now browse iPhone and download the file “/System/Library/CoreServices/SpringBoard.app/N82AP.plist”
• Edit the N82AP.plist file using any text editor and add the following key, value pair
  • <key>homescreen-wallpaper</key>
    <true/>
• Now upload the modified file to the same location and restart your iPhone

If you have followed the above steps correctly you will now be able to set wallpapers on your Springboard and Lock Screen by going to Settings > Wallpapers.