A Russian hacker Smolk published tutorial on how to jailbreak iOS 7.1 (7.1.2) running on iPhone 4, but the jailbreak is tethered. Below is a detailed tutorial. Note: This tethered jailbreak only for iPhone 4 running on iOS 7.1. Before jailbreaking, make a data backup for your device. Make sure your computer installed JRE 32-bit (download link) A tethered jailbreak means that whenever your iPhone is turn off you need to do a quick “Just boot” to get it back on. Steps: Step 1: Download iOS Soft Dev Pack JB v2 (Only for Windows) which is a software based on Opensn0w (created by Winocm) Step 2: Launch this tool after it downloaded. Step 3: Connect your iPhone 4 to computer and click “tethered jailbreak iOS 7.1 for iPhone 4” in the lower left corner. Step 4: You will see 3 easy steps appear on the screen shown above, click on “1）Run SSH RD Tool” A window as below will pop up, which takes a while. Step 5: Then manually enter your iPhone 4 into DFU mode, you will see the codes running until the green success appear. Step 6: Now, your iPhone is like this. After the green success appears, do not close the above white window, click on “2) Run SSH Connect” then there will be a black window. Please confirm whether the following code appears: Mounting /dev/disk0s1s1 on /mnt1 .. Mounting /dev/disk0s1s2 on /mnt2 .. If not, please click re-click 2) Run SSH Connect, until the black window and the codes appear. Step 7: If all goes well, do not close the black window, click the button “3) Jailbreak data send” also a black window appears. Step 8: Wait until the windows automatically closed, the phone will reboot, and then there’s a iTunes & USB logo, then choose the phone model belongs your iPhone belongs from the“Tethered Boot”buttons, model can be viewed at the back shell of the phone. Step 9: But no Cydia icon after reboot, do not worry, don’t touch your iPhone, over forty-five minutes, the phone automatically restart, iTunes & USB appears again, then click the button again,then you will see Cydia icon after the device reboot again, but still need to wait until phone respring. Wait a while, you can enter cydia, Congratulations, iPhone 4 is jailbroken. This jailbreak utility is new so you may faced some weird errors or unable to jailbreak your device. Just try a few times and it should work. I tested it on my iPhone 4.