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This guide assumes you have SSH installed on your jailbroken iPhone running 1.1.1 firmware. If you don't, the following guides will get you up to speed:

Dev Team Jailbreak 1.1.1 from 1.0.2 Windows

Dev Team Installing SSH 1.1.1 Windows

If you haven't already, now would also be a good time to install BSD World on your phone before proceeding, although it is not required. Follow this guide: Dev Team Install BSD World 1.1.1 Windows

Step 1

Download and open WinSCP: Available here!

Connect to your iPhone.

IP Address: Check your current WiFi settings on your iPhone.
(If you have trouble, try issuing a static IP.)
Login Name: root
Password: alpine
Connection Type: SCP
Port: 22

You should already have springpatch from when you jailbroke your phone. If not you can find it here: Everything you need to jailbreak your iPhone to 1.1.1

Step 2

Navigate to the /usr/bin/ directory om your iPhone.

Drag-and-drop springpatch to the /usr/bin/ directory of your iPhone. Before pressing the Copy button, press More >> to reveal more options. Check the box next to "Set permissions" and make sure the textbox has this text:

rwxr-xr-x

When you're done it should look something like this:

Once your options look similar, press the Copy button.

Step 3

Now press Ctrl + T to open WinSCP's console window. Simple type springpatch and hit execute. Hopefully you see the following text:

  SpringBoard Patcher for iPhone v1.1.1
  Brought to you by the iPhone Dev Team
  Successfully patched /System/Library/CoreServices/SpringBoard.app/SpringBoard
  Original backed up to:
          /System/Library/CoreServices/SpringBoard.app/SpringBoard.original.
  Please reboot your iPhone or kill springboard for changes to take effect.

Congratulations!

Excellent! It might not look like much has changed, but once you reboot your iPhone, you will be able to add third-party applications to your phone (and have their icons actually show up)! Of course this means the next guide is Dev Team Install AppTapp Installer 1.1.1 Windows