i've upgraded my iphone 4.1 to 5.1.1 (9b206) it starts but after sometime it stuck in restore mode in itunes & won't boot even with redsn0w. whenever i prefer just boot via redsn0w it shows only white screen & redsnow show iphone2,1_5.1_9b176 which is not available SHSH Blob for my iphone 3GS. i saved my SHSH blobs via tinyumbrella. What to do?