Last night we checked-in on the progress made towards bringing an untethered jailbreak to the iPhone 4S. The developer working on the hack, pod2g, had run into some trouble dealing with the cache on the smartphone’s A5 processor. He wrote that he had some idea of how to move past it, but that it might just take a lot of trials to get find what works. Now he’s made another announcement of further progress, and it looks like we’re nearly ready to see the fruits of his labor.
The cache issue pod2g was dealing with was something new introduced by the presence of a dual-core CPU. After getting his head around how the A5 was processing instructions, pod2g tried running his exploit in a single thread, and cleared the processor’s caches at just the right moment to ensure that his code executed as intended.
Apparently this took literally hundreds of different attempts to get everything working right; we’re just glad pod2g was dedicated enough to stick with it. It looks like there are some lingering stability issues to address, but we’re likely to see an untethered jailbreak on iOS 5.0.1 for even the latest Apple hardware in the very near future.