Firmware Update

Step 1: Download Pangu for Windows from here.

Step 2: Right-click on the Pangu icon and then click on Run as Administrator.

Step 3: With Pangu up and running, connect your iPhone, iPad or iPod touch to your PC using USB.

Step 4: Click on the checkbox that says PP to uncheck it.

Step 5: Press on the big blue button in the center of the display to begin the jailbreak process. Your device will reboot couple of times during the process so be patient.

Step 6: Once the jailbreak is complete, you’ll see a new Pangu icon on your iOS device’s home screen. It’s there to confirm that the jailbreak was successful.
Install OpenSSH
First and foremost, you’re going to download and install OpenSSH.
Step 1: With your iOS device connected to a Wi-Fi network, tap on the Pangu icon on your home screen.
Step 2: Now tap on the OpenSSH option.
Step 3: Tap on Install on the top right-hand corner of the display.
Let the installation process complete before moving forward.
Install Cydia After iOS 8 – 8.1 Jailbreak
Step 1: If you haven’t already, make a backup of your device’s content.
Step 2: Download the latest Cydia .deb file from here. You’re also going to be download the cydia-Iproj file from here.
Step 3: Once the .deb files are on your machine, you’ll need to SFTP the file onto your device. To do this, Mac users should opt for Cyberduck, while those on Windows are advised to use WinSCP.
Step 4: On your device, navigate to Settings > Wi-Fi, and find the hotspot that both your device and PC / Mac are connected to. Next to the connection’s details, hit the "i" and make note of the IP address.
Step 5: Using your designated SFTP client, key in the IP address as well as "root" for username and "alpine" for the password; ignoring the quotations, of course.

Step 6: Once the file browser appears, drop the .deb files in the root folder of your device.
Step 7: This is where things might get a tad tricky. Next, you’ll be firing in commands that you may not be familiar with, so ensure to watch closely if you’re not familiar with this process. To start an SSH command line session on Windows, hit Ctrl + T and on Mac, hit ⌘ + T.
Step 8: Finally, you’ll need to run the command:

dpkg -i cydia-lproj_1.1.12_iphoneos-arm.deb

Now run this command:

dpkg -i cydia_1.1.13_iphoneos-arm.deb

Step 9: Reboot your device.