Apple released iOS 4.2.1 GM to developers a couple days ago, and this new build can already be jailbroken using RedSn0w, as confirmed by Redmond Pie.

Even though the jailbreak process of iOS 4.2.1 GM is successful, it won’t take you too far as Cydia doesn’t work properly with iOS 4.2.1 and will crash at launch. If you know your way around the iPhone files, you can however SSH into your iPhone to manually install jailbreak applications.

Installing and jailbreaking iOS 4.2.1 GM is fairly easy, but it’s worth noting you should stay away from it if you rely on an unlock for your iPhone. iOS 4.2.1 GM will update your baseband, and most likely make it impossible for you to unlock for a while.

This being said, here is how to jailbreak iOS 4.2.1 GM with RedSn0w

Simply download RedSn0w 0.9.6 beta 2 and follow our previous RedSn0w tutorial. The step by step instructions are exactly the same. As explained in this tutorial, you should point RedSn0w to iOS 4.1, and not to iOS 4.2.1 GM.

This should work for the iPhone 4, iPhone 3GS, 3G, iPad and iPod Touch.

If you dare giving this a try, please make sure to share your experience by leaving a comment below.

  • James

    Nice to see it still works in the GM…GM. Soon after its official release we should hopefully see a update with working Cydia then 🙂

  • Anabell

    Does it really work?? Or will it break my phone……..literally.

  • Julien

    When will their be a unlock for iphone 4 4.1???

  • IK

    On 3gs: cydia not working now and a can’t connect over SSH. Is openSSH in the redsnow included? Any idea please…

  • James

    It’s not worth using this yet unless, just a good thing that the jailbreak works. The apps including Curia need to have the updated versions released. Wait a few more days folks.

  • James

    It’s not worth using this yet unless, just a good thing that the jailbreak works. The apps including Cydia need to have the updated versions released. Wait a few more days folks.

  • James

    Curia?? Damn that auto correct. LOL.

    • IK

      Curia is nice 🙂 Good idea!!!!

  • dappa

    Need to unlock Iphone 3g with 4.1, any news yet?

  • I have iphone 3gs ios 4.2 gm and modem firmware 05.15.04 ….pls say to how to jailbreak my iphone 3gs

  • Damien Hooper

    Cydia does not work with firmware 4.2.1. It installs properly but doesn’t open up upon activation!