
You can continue using your iPhone as usual, syncing files, etc., while still maintaining the jailbreak you already have. Step 3) Download Redsn0w 0.9.6b4 from the link given at the end of this post. Use the IPSW file that you have downloaded in Step 1. Step 2) Using iTunes 10.1, Update/Restore your iOS device to iOS 4.2.1.

Download links are given at the end of this post. When you connect your iPhone, you can just say “no” to the same prompt with no harm done. Download it according to your iOS device. iTunes will prompt you when you connect an iPad to your computer to upgrade and you can proceed normally.
#REDSN0W 4.2 1 INSTALL#
The good news is that you can still upgrade your iPad to iOS 4.2.1 to take advantage of all the new features but not have to install the same software on your iPhone.

In other words, it’s up to you on this one – jailbreak if you must or wait to upgrade. iOS 4.2.1 GM Jailbreak with Redsnow 0.9.6 b2 on iPhone 4, 3G, 3GS and iPod Step 6: Press the Next button after Redsnow identifies the IPSW file successfully. Nor are these devices as likely to be completely drained of battery juice like the iPhone is, especially if you make a lot of phone calls. Follow the directions on the screen to put your iOS device in DFU mode. Now, select ‘Just boot tethered right now’ and click next. Look for iOS 4.2.1 that you saved on your desktop and select it. Step 3) Download Redsn0w 0.9.6b4 from the link given at the end of this post. Open redsn0w 0.9.6.b4 and click on browse. Unlike redsn0w 0.9.6 this is untethered, so there is. Step 2) Using iTunes 10.1, Update/Restore your iOS device to iOS 4.2.1. Some people have reported crashes on other processors, so this may not work on older phones. The Dev Team just updated RedSn0w to version 0.9.6b4, which will jailbreak iOS 4.2.1. Being “tethered” is less of a hassle on iPod Touch and iPad, however, as maintaining a jailbreak isn’t as mission-critical on these devices. You can jailbreak iPhone 4, iPhone 3GS, iPod Touch 2G, iPod Touch 3G, iPod Touch 4G, iPad and Apple TV 2G. This worked for me on my iPhone 5S on iOS 8.1.3, not sure if it will work on other devices especially A5. iPhone 3GS/3G users who stuck with baseband 05.15.04 and 05.14.04 need to update baseband to 06.15.00 which is unlockable.
#REDSN0W 4.2 1 FOR MAC#
So unless you really need 4.2.1’s AirPlay or AirPrint features, we would suggest iPhone users hold off on this one, as an untethered (read: “normal”) jailbreak is in the works now. Redsn0w 0.9.6b5 for jailbreak iOS 4.2.1 Y update baseband to 06.15.00 it's out now Can download RedSn0w 0.9.6b 5 for Mac and Windows from the links below.
