Originally, the iPhone 3GS can record 640×480 videos @ 3Mbps. Mike Pan, after having a look at the ARM Cortex processor that the iPhone 3GS uses, discovered that iPhone 3GS can handle 720p encoding because of the capabilities of the processor. He was able to by pass the artificial limit that Apple has placed to enable the HD video recording. This method enables the non-standard resolution of 1080×800 for HD video recording. Mike opted this resolution to maintain the aspect ratio. Here is the sample video quality after enabling HD video recording on an iPhone 3GS.

Here is how to do it:

Before you use this method you must know:

  1. This method is tested on iOs 4.1.
  2. You need to jailbreak your iPhone 3GS. Follow these guides to jailbreak your iPhone 3GS if you haven’t
    - Jailbreak iPhone 3GS running iOS 4.1 with Limera1n.
    - Jailbreak iPhone 3GS (old bootrom) on iOS 4.1 with sn0wbreeze.

How to enable HD video recording on an iPhone 3GS:

This method requires you to SSH your iPhone 3G. It is a process to access your iPhone’s files remotely. To SSH, follow these steps:

  1. Run Cydia, search for OpenSSH and install it.
  2. Restart your iPhone.
  3. Connect your iPhone to your PC or Mac and make sure iTunes isn’t running.
  4. To access iPhone via SSH, you need to install CyberDuck for Mac or WinSCP for Windows.
  5. Login to your iPhone by putting the following details:
    - Server: The ip address of your iPhone 3GS
    -     Username: root
    -     Password: alpine
    -     Protocol: SFTP (SSH File Transfer Protocol) or SCP

After setting up SSH. Do the following steps to remove the artificial limit put by Apple to enable HD video recording.

  1. Download the pre-edited files HDVideo3GS.zip and unzip the content.
  2. SSH to /System/Library/CoreServices/SpringBoard.app/ and copy N88AP.plist (from HDVideo3GS.zip) here.
  3. SSH to /System/Library/PrivateFrameworks/Celestial.framework/N88/ and copy (from HDVideo3GS.zip) here.
  4. SSH to /System/Library/PrivateFrameworks/Celestial.framework/N88/ and copy CameraRollValidator.plist, MediaValidator.plist and AVCapture.plist(from HDVideo3GS.zip) here.
  5. Restart your iPhone 3GS.

[via iThinkDiff, RedmondPie. Source MikePan’s blog]