Help with jailbreaking and Cydia for iPhones, iPads, and iPod touches.

Simply open redsn0w 0.9.15b3 and go to extras>SHSH>New and select the 6.0.1 IPSW. This will make that message disappear.

See this FAQ answer:

This means that Cydia hasn't yet been able to save SHSH blobs for your device. Whenever you open up Cydia, it tries to grab any available SHSH blobs that Apple is providing for your device, and if it hasn't grabbed any yet, you'll see the TSS request message.

(SHSH blobs are "signatures" that let you restore to the iOS version that the blobs have been saved for. Learn more about what SHSH blobs are and why they're useful.)

Cydia might not be able to grab SHSH for your device for various reasons. Apple generally only "signs" the very latest version of iOS for your device, and Cydia might not yet be saving SHSH for that version.

Generally you only have to be concerned about SHSH when you need to restore your device and want to restore to a version Apple isn't signing anymore, for example to retain an untethered jailbreak. It's nice to have SHSH saved for the future, but you shouldn't worry too much about the TSS request message.

You can also save SHSH manually by plugging your device into your computer and using TinyUmbrella or the "Fetch" feature of redsn0w. Another option is to install the iSHSHit package on your iOS device, which will let you generate and email SHSH blobs for an additional backup, but you should then get those emailed SHSH blobs and import them into TinyUmbrella, as SHSH blobs by themselves can't help you restore.