So as it turned out, the Verizon iPhone 4 is vulnerable to Limera1n bootrom based exploit, and untethered GreenPois0n kernel based exploit which makes it possible to jailbreak on iOS 4.2.6, untethered using GreenPois0n RC5.4.
Image Credit: John Sibiga
Step 1: Download GreenPois0n from the link given below.
Step 3: Now follow the following onscreen instructions to enter DFU mode:
- Press and hold the sleep button for 2 seconds
- Continue holding sleep; press and hold home for 10 seconds.
- Release sleep button; continue holding home for 15 seconds.
Step 5: Your iPhone should now be successfully jailbroken on iOS 4.2.6. Now start “Loader” found on the homescreen and install Cydia.
This is it! You are done !