I did the jailbreak 0.9.6b on my iTouch 64GB PC011LL Version 4.2.1 (8C148) and it seems to have installed. I now have the brown Cydia icon and have turned on Battery %. When I try to launch Cydia it just flashes the screen the same when I try to use Safari. it is logged onto my network and has internet access and the other apps seem to work fine. Any help would be appreciated.