But the condition that can downgrade to iOS 5.1.1 on iPhone 3GS / 4 and iPod Touch you. Still requires iOS 5.1.1 shsh. If you do not have the SHSH files, There is no way to be able to Downgrade iOS 6.1.3 to iOS 5.1.1.
For those of you who have iDevice with the A5 processor or higher, such as the iPhone 4s / 5 or iPad 2/3/4/Mini and already did upgrade to iOS 6.1.3, this method can not be used to perform Dowgrade to iOS 6.1.3 iOS 5.1.1, because iFaith not support the iDevice with the A5 processor or higher, even if you have iOS 5.1.1 shsh files. My advice still enjoy the current iOS, until hackers release new jailbreak tool.
if you want to downgrade iOS on iPhone or iPod, you should prepare the required
1. iFaith latest version, you can Download here
2. iREBrc7 you can Download here
3. IOS 5.1.1 SHSH Blobs file. you can requests from Cydia server, use TinyUmbrella or iFaith.4. iTunes Latest version
5. iOS 5.1.1 is compatible with your iPhone or iPod.
How to Downgrade iOS 6.1.3 to iOS 5.1.1 Using iFaith
Step 1: Open iFaith By Way, Right Click and select "Run As Administrator"
Step 2: On the screen iFaith, Select "Build * signed * IPSW w / Blobs" Then select "Browse for SHSH Blobs" Search iOS 5.1.1 SHSH file and click Open.
Step 3: Next, select "Browse for an IPSW" and Find Files Firmware iOS 5.1.1 that you download or prepared beforehand.
Step 4: Wait Until iFaith finished making a CTF file, so you just be patient enough, might use the time to 5-10 minutes.
Step 5: After iFaith finished making CTF file for your iPhone or iPod, please check the file, usually stored on your computer desktop.
Step 6: Next, iFaith will automatically guide you to position your iPhone or iPod into DFU Mode. But at this moment, we do not Using iFaith to position your iPhone or iPod into DFU Mode. So, Close iFaith
Step 7: Open iREB r7 that you downloaded earlier, By Way Right Click and select "Run As Administrator"
Step 8: Once your iPhone or iPod is detected in iREB r7, On the iDevice menu options, Please Choose according to your iDevice have.
Step 9: At this Moment, you will be guided by iREB r7 to position your iPhone or iPod Touch into DFU Mode. Please Follow the instructions that show on the screen of iREB r7
- Press and Hold the Power / Sleep for 3 Seconds
- Press the Home button without releasing the power button / Sleep for 10 seconds
- Without releasing the Power button Release the Home button (Home button remains in the press) for 15 Seconds
Step 10: After successfully position your iPhone or iPod Touch into DFU Mode, Close iREB r7, And Open iTunes, Now In iTunes your iPhone or iPod Touch will be detected as Recovery Mode.
Step 11: In iTunes Press and Hold down the Shift key on your computer and then click "Restore" in iTunes. Then Select the File CTF was created using iFaith, this file is usually located in your Desktop Computer.
Step 12: Please Wait Until Done Restore Process. and enjoy iOS 5.1.1
But You can Jailbreak TetherediOS 6.1.3, Please read this artitckel for it.
How to Downgrade From iOS 7 Beta to iOS 6.1.3 or iOS 6.1.4
How to Tethered Jailbreak iOS 6.1.3 Using Sn0wbreeze