Apple has ended the window for installing iOS 5.0.1 on your iPhone, iPad, or iPod touch. A5 devices are now immovable from iOS 5.1 if they have been updated until a solution for downgrading can be found. SHSH blobs will not do you any good for downgrading an A5 device at this time. Be extra careful not to "accidentally" update to 5.1 on an A5 device. A4 devices with saved blobs can still be downgraded as usual.