Having a tethered jailbreak can be a pain in the butt. Of course we knew this when we were jailbreaking our devices, but part of our job is to test these things out and help you streamline the process or help newer users know what to look out for.
Many of Us Are New To a Tethered Jailbreak
In this case, it's the tethered jailbreak, which we have written a bit about over the past few days. This is A) because some are totally new to jailbreaking and B) because even those who have been jailbreaking for a year or two may never have had to use a tethered jailbreak until now.
There are some things to keep in mind when using a tethered jailbreak. One is that you will have to plug into your computer every time you reboot your device. Otherwise, jailbreak applications will not work.
In a worst-case scenario, you've installed apps that use MobileSubstrate (which is inevitable), and those hook onto SpringBoard or other important programs. It that happens, you won't be able to boot at all. Your device will be stuck at the screen with the Apple logo.
The good news is that you won't have to worry about this if you have one of the older models: iPhone 3G, iPhone 3GS (old bootrom only) and iPod touch 2G (Non-MC only). People with those devices have the luxury of not having to plug in when they reboot their device.
Those of you who own any of the other iOS devices, however, not so lucky.
Why Many iPhone users May Want to Wait
This is fine on an iPad or an iPod touch, because devices like the iPad generally stay around the house, while the iPod touch isn't as vital to have operational as an iPhone. An iPhone you can't turn on is trouble, especially while traveling. That's why we suggest holding off until the untethered jailbreak is released.
But I Really Want a Jailbreak, What Can I Do?
So you really want to jailbreak your iPhone on iOS 4.2.1? Okay, but don't say we didn't warn you. If you must do this, then we suggest you create a backup on a USB stick. This wil l save you lots of heartache if you have to reboot your phone while not at home. The only problem? You'd better home someone has a computer within easy access, and is willing to let you plug your phone into it. You will also have to carry around your cord, it's all very inconvenient.
Create a disc image and on your USB stick, you will want to save the files you need: the jailbreak tools (in our case it's RedSn0w) and the ipsw file for your current firmware:
Now attach that baby to your keychain and carry around your cable. (Not very convenient, huh?) In the event that your iPhone runs out of power, or your device has to be rebooted, you can plug into the USB drive and use RedSn0w to run your tethered jb again.
That's all we can think of for now. It's not the most efficient way to jailbreak, but it works, and it's better than nothing. Still, we strongly suggest that iPhone users stay away from the tethered jailbreak. If can cause more trouble than is needed.
That said, if you are sure you want to jailbreak, check out our guides here: