Apple recently released iOS 4.3.5 to patch a few security vulnerabilities, and RedSn0w has already been confirmed to offer a tethered jailbreak on Apple’s latest firmware.

If you’re on an iPhone 4 with an unlocked baseband, jailbreaking iOS 4.3.5 with RedSn0w will not preserve your baseband. Luckily, a custom build of PwnageTool has been released to fix that problem.

The folks at Redmond Pie have put together a custom PwnageTool bundle for the iPhone 4 that will jailbreak iOS 4.3.5 and preserve an already-unlocked baseband. Newer basebands do not receive an unlock.

You’ll need iOS 4.3.5, iTunes 10.4, a tetheredboot utility, and PwnageTool 4.33, which you can find in our downloads section. (PwnageTool is Mac-only software.) To learn how to jailbreak with PwnageTool, refer to our tutorial.

To get the custom build of PwnageTool that you’ll need to keep your iPhone 4’s unlock, head over to Redmond Pie and download their custom build package. They have a guide on how to modify PwnageTool with the custom build, too.

It’s recommend that all jailbreakers stay on iOS 4.3.3 for the most up-to-date untethered jailbreak. You can jailbreak all iDevices on 4.3.3 with JailbreakMe.

Let us know if you decide to use PwnageTool on iOS 4.3.5. Or are you staying on 4.3.3 to keep your unlock?