Hello. Is it possible to downgrade an iphone 3GS with 6.1.3, baseband 05.16.08, to any iOS lower than that without the SHSH blobs? I want to unlock this phone, but apparently I can only do a tethered unlock and that won't do it for me, so I was thinking I could downgrade it and then unlock it. I have the SHSH blobs for 4.3, but that's it. Nothing newer. and 4.3 seems a bit low. Any ideas? Thank you.