Developer pod2g is making progress on an untethered jailbreak for A5 chip based iOS devices which would include the iPad 2 and iPhone 4S. Issues with the jailbreak were apparently caused by processor cache issues, but the A5 cache is no longer a problem.
OK, figured it out, the A5 cache is not a problem anymore.
I sorted it out by doing the untether in a single thread and by flushing all the dcache then all the icache in a row at a strategical point of the process.
This jailbreak is being making progress with the help of Saurik who helped find yet another piece of the puzzle.
No timing on a release just yet, but it’s good to see progress. Let’s hope for that illusive untethered jailbreak for iOS 5.
Source: pod2g
Written By 
How do I jailbreak my iPhone 4. Iso5.1.1. What do I do. Please help!! Thanks