follow step by step
Step 1: Connect your A5 device to your computer and run RedSn0w 0.9.11b1.
Step 2: Click jailbreak, and you will see an info window appear.
Step 3: On your iPhone you will notice a new profile window. Tap Install > Install Now > Next (no password) > Done.
Step 4: You will see another info window via RedSn0w.
Step 5: Enable the VPN option in Settings and the jailbreak will be triggered.
Step 6: You may notice VPN errors, these can be ignored. The device will reboot, and once it reboots you will notice Cydia on your Home screen.
That’s it! There’s no DFU mode involved or anything like that, so this is one of the easiest jailbreaks to accomplish. It works pretty much the same as the Absinthe jailbreak, but I found RedSn0w’s Corona implementation a little more reliable than Absinthe. This was performed on a Windows machine, but it works exactly the same on a Mac.