The method introduced here is pretty ugly, if you prefer easier method, wait for some days.
Requirements
1. Intel Mac Tiger (Leopard may work as well)
2. iPhone running version 1.1.1.
3. No Installer packages installed. If you’ve installed any packages, remove them or remove the Installer directory from /var/root/Library (thanks billymayes). If you have packages installed before updating, Installer will think you have them after the update and cause problems.
NOTE: scrolling is not turned on by default in 1.1.2. To scroll your list of applications, install SummerBoard.
Create Symlink
Visit Jailbreakme.com and jailbreak your iPhone. When it’s finished, you should have Installer.app on your home screen. If you already have Installer, you don’t need to do this step.
Plug iPhone in and open iTunes. Make sure that you have the “Update” button available in iTunes before proceeding.
Open up Installer, navigate to the “Tweaks (1.1.1)” category, and install “OktoPrep”. You may also achieve this by manually typing the following command thru SSH:
mknod ~/Media/disk c 14 1
Upgrade to v1.1.2
In iTunes, hold option (for Windows hold shift) and click “Upgrade”. At the prompt, select the iPhone1,1_1.1.2_3B48b_Restore.ipsw file. Once upgraded to 1.1.2, close iTunes.
Jailbreak
Download iPHUC (Jailbreak112) and the readline library (Readline Library) if you don’t have it yet. Extract the contents so that iphuc, fstab, and iphonefs are all in the same folder.
Open a Terminal, type
cd ~/<folder to hold iphuc> ./iphuc getfile disk iphonefs/disk.dmg 314572800
The getfile command will take about five minutes. Once complete, there will be a file named “disk.dmg” in your “iphonefs” folder.
Double click the disk.dmg to mount it. Open the newly mounted Oktoberfest3B48b.UserBundle drive and open the “etc” folder. Replace the fstab file inside the “etc” folder with the supplied fstab file.
Download AppTapp Installer from Nullriver and place it on your desktop.
Control click “AppTapp Installer” and click “Show Package Contents”. Navigate to Contents>Resources. Copy Installer.app from the “Resources” folder over into the “Applications” folder inside Oktoberfest3B48b.UserBundle. Do the same for libarmfp.dylib, placing it inside usr>lib instead of Applications.
Unmount the image. Back in Terminal, assuming that you’ve kept iPHUC up and running, type:
putfile iphonefs/disk.dmg disk
This will take another minute or so. When it’s finished, reboot the iPhone and close Terminal. You’re jailbroken!
After the phone reboots, activate with iTunes and uninstall “OktoPrep” using Installer.
That’s it! If everything went well, you should be enjoying a freshly updated and jailbroken iPhone. If we missed anything, let us know in the comments.
Original from iPhoneAlley.