As a new jailbreaker you may not be aware of the existing solutions for different iOS versions. Many of iPhone 4 users who have updated to 6.1.3 are now looking for a solution on how to jailbreak iphone 4 on ios 6.1.3. Currently there is only one legitimate and tested software available which you can use to jailbreak iphone 4 on 6.1.3, which is of course redsn0w the old and most used software. But the problem with existing tool is that it is tethered and also requires to download 6.0 firmware for conducting the jailbreak of 6.1.3, which is due to the limera1n exploit that works with ios 6 only. Therefore when you jailbreak 6.1.3 on iPhone 4 you will also download and select the 6.0 firmware during the jail break process.
Also one must note that this will be a tethered solution that means you need to use a computer and redsn0w program in case you want to reboot your iPhone 4 although it is no problem if you reboot without redsn0w the difference will be that two programs will not work i.e. Safari and Cydia other iPhone functions will be OK. If you are looking for an untethered 6.1.3 jailbreak for iphone 4 then sorry right now there is no solution available for untethered JB of 6.1.3,
Procedure to jailbreak iPhone 4 ios 6.1.3
Step 1: As always we recommend our visitors to backup their iphone before starting the JB process, you can simply start iTunes while your iphone 4 is connected to computer and in the middle of the iTunes screen click backup and make sure to select backup to this computer before clicking backup.
Step 3: Now turn off your iPhone and connect it to computer and run the redsn0w program as administrator. You will see main redsnow window, go to Extras => Select IPSW and select the file when asked by the tool. Once you click open the software will give an information pup up message and nothing will happen more.
Step 4: Now go to main window and click jailbreak after a while the program will ask you to make selection from different options. Just only select Install Cydia and un-check all other options, and press Next.
Step 5: The program will give you a window with next steps i.e. turn off your iPhone 4 and put in DFU mode. DFU or direct firmware update mode is very important step to start a jailbreak process. Therefore you should understand the steps carefully. If you are a new jailbreaker then you may be a little bit confused because you may need to try many times to put your device in dfu mode. Don’t panic just press the key combinations as mentioned in the redsn0w screen and if you fail in one try don’t touch the program and try the same combination again and again, as soon as you will do correctly the program will proceed automatically and you will see activity on the redsn0w screen.
Step 6: After you have put your iphone 4 in DFU mode now just relax and see the jailbreak process completing automatically. After a while you will see your iPhone 4 rebooting and also redsn0w i.e. pineapple icon on your iPhone screen with a progress bar. Once device becomes ready it means it is now jailbroken and we need last step of booting tethered.
Boot Tethered to jailbreak iphone 4 ios 6.1.3
Step 7: Select again the ios 6.0 ipsw file as we did in step 3, and then go to Extras => Just boot. Again you will need to put your device in DFU mode and remaining part will complete automatically. After the iPhone 4 is rebooted you will see it is now having Cydia on it and now you can run the Cydia 6.1.3 to install the 6.1.3 jailbreak tweaks and themes etc.