Step 1: Download PwnageTool 4.1.2 for Mac
Step 2: Download the most recent version of PwnageTool Bundles from msft guy here, then extract it to your computer's desktop.
Step 3: Copy PwnageTool you have download to your desktop. Right click, and select “Show Package Contents”.
Step 4: Browse to Contents > Resources > FirmwareBundles.
Step 5: Now copy this custom bundle iPad1,1_4.2.1_8C148.bundle to its location and close the folder.
Step 6: Use Cydia binary from http://apt.telesphoreo.org/cydia/debs/cydia_1.0.3222-73_iphoneos-arm.deb, start “Terminal” program from your Mac and then run the following:
Step 7: Start the patched version of PwnageTool, select iPad as your device and you'll notice that PwnageTool will automatically detect iOS 4.2.1 GM firmware.
Step 8: Now follow the following steps to enter DFU mode:
- PwnageTool should automatically detect the correct iOS firmware for your device.
- On seeing this message, hit "No" to preserve your baseband to be able to unlock.
- PwnageTool will start creating the custom pre-jailbroken firmware for your device.
Step 9: After creating your custom firmware successfully, you will have to restore your iPad to the firmware cooked by patched PwnageTool by clicking on the iPad icon on the left sidebar of iTunes then hold left “alt” button (“Shift” button on Windows) on the keyboard and then click on “Restore” then release the alt button, and select the custom firmware created by PwnageTool.
Step 10: Now sit back and enjoy as iTunes does the rest for you. This will involve a series of automated steps. Be patient....and wait while iTunes installs the new firmware 4.2.1 on your iPad or iPod touch 4. Your iOS device screen at this point will be showing a progress bar indicating installation progress.
Step 11: Once the installation is done, your iPad will reboot and you'll get a jailbroken iPad on iOS 4.2.1 with a working version of Cydia on it:
There are still issues with Cydia crashing when trying to customize categories, but installing and updating packages seems to make it work OK. Also, this guy is currently working on a bundle for iPod touch...
mv Cydia_ Cydia.bak
bspatch Cydia.bak Cydia_ Cydia.patch
Then copy to /Applications/Cydia.app/Cydia_
and chmod +x+s /Applications/Cydia.app/Cydia_