Thanks to Semaphore (creator of tiny umbrella) for this information:

It seems that Apple has decided to put a baseband requirement on iOS. So at this point, if you are using Saurik’s server or tiny umbrella and trying to restore 4.2.1 on an iPhone 4, you will end up in recovery mode and tiny umbrella will not be able to pull you out of recovery. In this case, you will have to restore 4.1 again or you will have to restore 4.2.1 stock and be tether jailbroken. (Of course, I recommend 4.1 and not bothering with 4.2.1 at all). If you are an unlocker, this is a no brainer. Do not update to 4.2.1 even to test it at this point.

Edit: Redsn0w 0.96b4 is out and jailbreaks correctly 4.2.1. However, it is tethered on most new devices (read below). And refer to the jailbreak chart to see how your device fits in.

So 4.2.1 is out and you have all heard Geohot state that his limera1n exploit means you can jailbreak all devices forever. So why shouldn’t you update today?  This post will try to answer some common questions around this subject and try to explain why you should hold off.

First, jailbreaking is much more than finding an exploit and using it to get a Cydia icon. A proper jailbreak does a lot more. There are a series of kernel patches done to the device that make most jailbreak software work correctly. (Note that updated pwnage bundles by msftguy or such do not have these patches and key apps may not work).

Second, while limera1n and greenpois0n exploits may work, those tools will not. You will need them to be updated before they can be used to jailbreak your 4.2 device.

Third, the spirit portion of the 4.1 jailbreak used in limera1n and greenpois0n allowed the device to boot jailbroken untethered. That has been patched by Apple and no fix to that problem is known yet. Therefore, even if you do manage to get an updated limera1n or greenpois0n, your iphone 4, iphone 3gs on newer bootrom, ipod touch 3 or 4, or iPad will all be tethered. This means after you run the tool it will boot one time and work jailbroken until you reboot. At that time you will get a “connect to itunes” logo and will have to rerun the jailbreak tool in order to get the device to boot again.

Now, tethered jailbreak isnt the end of the world. On an ipod and ipad, it’s probably not too bad. But on an iPhone, a device you may need to make emergency calls on the road, it really sucks. I strongly suggest all iPhone users that have tether jailbreak devices only to hold off on updating until this is solved. Me, I’m staying on 4.1 probably until iOS 5.

Which devices are not tethered? iPhone 3g, iPhone 3gs (old bootrom), ipod touch 2 (non mc). On these devices, you will find a pwnage tool bundle or updated redsn0w released soon. Unfortunately, these updates will not have updated kernel patches and, on 4.2, this will be more problematic that in the past.

Finally, let’s say you get past all these issues somehow. You jailbreak to install software. Most of you want either themes or some cool tweaks like sbsettings, folder enhancer, or bitesms. All these rely on mobile substrate. As of this posting, mobile substrate does not work on 4.2. That means that almost all jailbroken software will not run on 4.2 as of today. This is being worked on and will certainly be fixed shortly. But that is the state as of today.

As a side note, there’s just nothing provided by Apple’s 4.2 update that you got to have today. Seriously. What is so great that it’s worth removing all the great things you get by jailbreaking? If you have some problem on your device, do not expect it to be solved in 4.2.1. Apple always lists “bug fixes” but really, we never see anything useful from this. Waiting a week, two, or three to let these issues all get sorted out is your best bet.

Yes, Apple is releasing it today. No you should not update to it.

For those that did not read that, DO NOT UPDATE TO 4.2.  Ok now that you’ve read it, wait for the jailbreak to be officially tested and released. Further, remember that jailbreak on 4.2 is likely tethered on newer devices, which means you have to rerun it every time you reboot your device.  This was covered here already. Dev team also covered this in more detail here.

FullScreen for Safari, the tool which makes Safari a really great web browser, has been updated with cool new features. The overall experience is now much better. Many of the new features have been requested by users.

Changelog:

4.2 is out. Most of you should hold off on the update for now. If you have some bug you are hoping is fixed by 4.2, it’s not.

Worse yet, while limera1n and greenpois0n allow for 4.2 to be jailbroken, in most cases this is a tethered jailbreak. That means if you have to reboot your device, it shows a “connect to itunes” logo until you run the jailbreak software again.  I suggest not updating until something changes and your device is in the untethered jailbreak list (once tools are out):

iphone3g - will run 4.2 untethered. Redsn0w or such will be updated
iphone 3gs – old bootrom will run 4.2 untethered if done via pwnage tool while updating from 4.1. Otherwise it will be tethered.
iPhone 4 – tethered
iPod 2g – 4.2 untethered.
ipod 3g and newer – tethered
iPad – tethered.

Tethered jailbreak isn’t that bad for ipads and ipods. But if something happens and your iphone reboots while you’re away from your computer, you cant use the device until you get home and run something on your computer again.  The community is working on a solution to this to either make the jailbreak untethered or at least semi-tethered. Semi-tethered means the device will at least reboot, but unjailbroken while on the road until you return to your computer.

4.2 is about to be out. It’s nothing great for any of us. But it means iTunes will be prompting for an update, which of course you should decline. But the worst part….

Due to traffic reasons, Cydia didnt present the ‘make my life easier’ dialog. So many of you do not have SHSH stored for 4.1 which means once apple releases 4.2, you will never be able to restore 4.1 again. It’s critical that you download tiny umbrella and request your 4.1 SHSH today, while 4.1 is still being signed. You may have only a few days left of this opportunity.

You can tell if you have an SHSH for 4.1 in cydia’s home screen at the very top (although this may not yet be enabled in Cydia for all devices). You should see something like:
SHSH: iOS 4.0, 4.0.1, 4.0.2, 4.1

If you do not see the above line and / or it does not include 4.1, make sure you get tiny umbrella and get your SHSH now.

Download it here

Consider this urgent!

. FullScreen for Safari has received a major new update with many useful features, especially for one-hand users. new Gestures: One Finger Tap and Hold (a tap, then place your finger again and hold for a short time), One Finger Double Tap and Hold new Action: Open predefined URL (define a website which you can [...]

SwirlySMS free for iPad 3G is now available in Cydia. It is a free app without restrictions that gives you the possibility to send and receive native SMSes on your iPad 3G like you would do on any cell phone. See below for a few screen shots.

Ever wake up with an inbox full of Facebook emails? Annoyed by newsletters you’re not going to read anyway? Going through all of them just to get rid of the red badge just takes too much time. This is why we invented Mark Read, an easy way to mark either your entire inbox or just the emails you want as read/unread, right within Mail.app.

Greenpois0n, Chronic dev’s jailbreak tool is out. You can download it for both windows and mac (mac download coming soon). This is an alternative to Geohot’s release of Limera1n. If you already used Geohot’s tool you do not need to do anything else. If you are not jailbroken yet, you can choose which to use.

If you are getting host unreachable errors while trying to install pay packages, these are caused by Cydiastore payment check and need to be addressed by Saurik. It is not something I can solve on my end and (most importantly) my repo is not down. You get an error message like “apt.thebigboss.org host unreachable”. But the issue is that the cydiastore check times out.

Currently, Saurik is out of town on a conference so this may not be solved for a couple days.

Geohot just released Limera1n. This is an iphone 4.1 jailbreak for all devices.  From Geohot:

limera1n, 6 months in the making

iPhone 3GS, iPod Touch 3G, iPad, iPhone 4, iPod Touch 4G
4.0-4.1 and beyond+++
limera1n is unpatchable
untethered thanks to jailbreakme star comex
released today to get chronicdev to do the right thing
brought to you by geohot
Mac and Linux coming soon
follow the instructions in the box, sadly limera1n isn’t one click
that’s the price of unpatchability
as usual, donations appreciated but not required
still in beta, pardon my ragged edges
zero pictures of my face

Download here.

If you follow iRealSMS on twitter or visit the website you might have been taking part in the the beta testing for iRealSMS 3.0s latest update. With the beta now over, iRealSMS 3.0.4.5 update has been submitted to the BigBoss repo and should be available now. What is included in the new update is a [...]

- The developer of Firewall iP and ScreenDimmer brings you EnhancedTabs, which adds improved functionality to Safari’s tab handling. And the best: it is free! Change the “Open in New Page”-behavior to normal (nothing to explain here ;)) stop at tab overview: Safari won’t go directly to the new page but instead stop at the [...]

Update: Some sites have wrongfully stated that NoLockScreen bypasses any lock screen password protection, this is not true. Just wanted to give you a headsup on this cool new 2 free tweaks I recently did: NoLockScreen – disables the need for always sliding that annoying bar each time you need to unlock your device. If [...]