Apple has recently released iOS 5.1 Beta to developers. notcom the developer behind TinyUmbrella has updated his tool to support iOS 5.1 Beta. Download now.
TinyUmbrella Updated To Support iOS 5.1 Beta
From thefirmwareumbrella blog:
Before you ask; Yes a solution for the 5.x firmware nonce is being investigated… None of us have a working solution yet though. Hang tight.
I have a couple trails and ideas I am trying out for 4.x baseband based restores to avoid 10xx errors. Until then save your signatures as you will never know when they may come in handy…
Although there isn’t an untethered jailbreak available right now for the iPhone 4S or iOS 5 but we recommend that you save your SHSH Blobs just in case.