iv been looking around and it looks like only mac has a JB, anyone know one for windows or anyone with a mac wanna lend a hand and JB 2 phones.
What firmware version?
yea haha that would help. 4.2.1
Nothing for windows now, but it looks like it’s coming.
There is no untethered exploit for any version yet on the iPhone 4 hardware yet.
Well, 4.2.x anyway. I’m happily still running 4.1 with an untethered JB on the iPhone 4.
yea must be nice… mine came 4.2.1 outa the box 
You can jailbreak 4.2.1 untethered on iPhone 4, and have been able to for about a month now… You need redsn0w 0.9.7, iOS 4.2b3 SHSH blobs, iOS 4.2b3 ISPW, iOS 4.2.1 ISPW, and a mac.
If the phone is new, and has 4.2.1 installed, you’re screwed as you can no longer get iOS 4.2b3 SHSH blobs. Wait for 4.3, and save youre SHSH’s in the meantime.
how do you save your SHSH blob’s if your not alrdy jailbroken?
Tinyumbrella
Untethered for 4.2.1 is out now. http://greenpois0n.com/
Site is down, must be getting HAMMERED right now.
RC5 is only for Mac right now so looks like i still got to wait
Here - http://lifehacker.com/#!5754463/how-to-jailbreak-your-ios-421-device
So if I want to do this and my device is already jailbroken, I will need to save everything too itunes, upgrade to latest firmware, jailbreak again, and then reload everything. Will all my games reload?
There is a app in cydia that saves all your downloaded stuff from cydia. So that when you re jailbreak it rememberes what you had and reloads it all.
Updating a jail broken device always de-jailbreaks it. What I usually do is a restore to the new version, then restore from a backup before the update. Data from all app store apps should be there, even if the app was stolen and isn’t loaded yet. You could use one of several utilities to remember what jail broken apps you have… And if you’re big on stealing apps, you can just enable app sync, sync them to iTunes, then update, JB, and load them back on via iTunes.
What app is that?
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So I should make a backup because I have yet to make any backups. How can you do a restore to the new version if it isn’t downloaded/installed yet? Do you mean download/install, then restore from a backup?
What are some of the utilities names and how do I get app sync?
AppSync is available in Cydia, but I don’t like it. Unless you absolutely cant memorize the packages you have installed, its crap. Backups are done when you sync in iTunes. You restore to a new version by hitting the restore button in iTunes. It picks the latest version by default, since that is the ONLY version you can ever install on of the newer iOS devices. Apple/iTunes will never allow you to install anything but the most current version, without tricking it with saved SHSH’s from previous versions.
App Sync is built into Installus, if you use it. If you don’t steal apps, which you shouldn’t, you have absolutely nothing to worry about. In Installus, there is a settings box, in there is App Sync, off by default, toggle it on and reboot. Then when you sync to iTunes, it SHOULD copy the cracked IPAs. This can be a picky process, sometimes it just wont work.
Yea iv never actually used it. I just memorize the packages I use. Only takes a few min to get em all back. So sync your phone with iTunes, then update to the 4.2.1 then rejailbreak with greenpoison. And reinstall all of your cracked apps and packages from cydia.
oops, should of said this was for my ipad.
iPad isnt any different, in terms of jailbreaking.