From ModMyi - Wiki

You can now do this jailbreak directly from Installer.app!

Just released is the dev team jailbreak for 1.1.3!

Here is a quick guide to get you and your iPhone up-to-date:

Requirements:

You MUST have a 1.1.2 Jailbroken phone with SSH and BSD subsytem (1.5+) installed! If you dont Click Here
You MUST set your Auto-Lock to Never (Settings > General > Auto-Lock)

Simple Answers

Q: If i have an iphone at 1.1.1, can i update from 1.1.1?
A: No you have to update to 1.1.2 before running the 1.1.3 jailbreak

Q: Will my unlock stay?
A: Yes, your unlock should stick because the baseband and corresponding Kernel isnt updated, only the firmware is flashed!

1.1.3 Dev Team Jailbreak

Get the 1.1.3 jailbreak file here (rapidshare)

Unzip your download




Open your Jailbreak-1.1.3 Folder




I always like to start by reading the README file!




Launch Cyberduck or the SSH client of your choice (this guide assumes you know how to SSH into your phone) if you need to revisit this topic Click Here




SSH into your iPhone (root, alpine).




Copy over all of the files that are in the Jailbreak-1.1.3 folder to your / (root) directory. Not the folder, the contents.




Now open up a terminal session and SSH into the phone (root, alpine)




Now that you are connected to your iPhone you need to run the install.sh script. You do this by typing in the command prompt

/install.sh


Your terminal window should start off like this:




And continue to update...




Dont worry it will take 10-12 minutes to completely run. Don't touch it! I may look stalled, but its not!




Finally end with this:




At this point your iphone will reboot and be flashed with a soft-update of FW version 1.1.3. You notice you get a prompt explaining the wiggly icons! YAY!

Congratulations you have updated your iphone and not modified your baseband!