What’s in a name?

What’s in a name?  Well in the case of an HFS volume name on iOS, an untether exploit — as the Chronic Dev Team revealed last week with an untether for the 4.2.1 jailbreak, which had previously been a tethered JB for most recent devices since 4.2.1’s release in November.  With their permission, we’ve incorporated their 4.2.1 “feedface” untether into today’s PwnageTool 4.2.  This means iPhone unlockers can safely restore to a custom 4.2.1 pre-jailbroken IPSW and retain their current baseband and unlock.  PwnageTool also supports all the other 4.2.1 devices other than iPod touch 2G:

• iPhone3G
• iPhone3GS
• iPhone4
• iPhone4-Verizon
• iPod touch 3G
• iPod touch 4G
• iPad
• AppleTV 2G

PwnageTool also includes two very recent improvements to the 4.2.1 JB:  iBooks was just fixed by @comex and @pushfix last night so that it works as intended on DRMed books, and the wifi problem on AppleTV 2G was fixed by @nitotv, @DHowett, and @saurik.  Both of these fixes will also be available in upcoming Cydia package updates, so if you’re already jailbroken you can wait for those updates rather than restore and jailbreak again.
The various components to the 4.2.1 untether (including a second exploit involving Mach-o headers) were worked out by 0naj, posixninja, and pod2g, and a nice writeup by 0naj is available on the wiki. The actual injection method uses geohot’s limerain exploit for most devices.  And even though 4.3 is just around the corner, the exploit used has already been closed in the latest 4.3 betas, so it made sense for the 4.2.1 untether to be released when it was.  It also appears that a security researcher named @i0n1c has a 4.3 untether ready for when Apple releases the final 4.3 FW, so it may not be a long wait at all with 4.3!
Feel free to ask for help in our comments section.  And thanks as always to our terrific moderators Confucious, sherif_hashim, dhlizard, Frank55, and subarurider!
Official Bittorent Releases
PwnageTool_4.2.dmg -> PwnageTool_4.2.dmg.6176918.TPB.torrent
SHA1 Sum = af365f5de19d7ee19cbe1c67b2f226996a46b3ac
Unofficial Mirrors
The following links are unofficial download mirrors, you download these archives at your own risk, we accept no responsibility if your computer explodes or if it becomes part of a NASA attacking botnet or even worse if your hands fall off mid-way during the use of these files. We do not check these links and we accept no responsibility with regard to the validity of the files, the other content that these links may provide or with the content that is on the third-party linked site.
Always check the files that you have downloaded against our published SHA1 hash.
We would prefer that you downloaded the official bittorrent release that is linked above, but you are welcome to try these if you really must.
Mirror owners should email direct dmg download links only (no rapidshare type sites please and please make sure that your web-server can serve DMG MIME types) to blog@iphone-dev.org — please don’t place mirrors in the comments as they will be deleted.

• http://www.hostmyapple.com/pwnagetool/PwnageTool_4.2.dmg
• http://www.macniouz.fr/softwares/PwnageTool_4.2.dmg
• http://dl.twiios.com/pwnagetool/PwnageTool_4.2.dmg
• http://public.stuff.hu/pwnagetool/PwnageTool_4.2.dmg
• http://crzz.co/dl/PwnageTool_4.2.dmg
• http://www.iphonews.eu/PwnageTool_4.2.dmg
• http://www.yourdailyapple.net/downloads/PwnageTool_4.2.dmg
• http://applerama.ru/pwnagetool_4.2.dmg
• http://riccardomastellone.com/files/PwnageTool_4.2.dmg
• http://up.iNeal.ME/PwnageTool_4.2.dmg
• http://claytonbraasch.com/downloads/PwnageTool_4.2.dmg
• http://www.zaone.ro/PwnageTool_4.2.dmg
• http://maclovr.com/PwnageTool_4.2.dmg
• http://cdn.nspwn.com/pwnagetool/PwnageTool_4.2.dmg
• http://stantheripper.com/PwnageTool_4.2.dmg
• http://ibloo.net/PwnageTool_4.2.dmg
• http://smotrikino.net/PwnageTool_4.2.dmg