5.1.1 Ipad 2 to 6.1.2 before jailbreak?

Hey, This may well be covered here somewhere already but I think I need it explaining. I have an iPad 2 running a JB 5.1.1 and tiny umbrella (on Mac 10.7.5) says that my SHSH are saved as follows: 4.3.5, 5.0.1, 5.1.1, 6.0.1, 6.1.3. So I want to update to 6.1.2 use Evasion and then restore from my backup. TU runs fine and says the TSS is running, then I'm trying to connect my iPad to iTunes and ALT upgrade to a stock 6.1.2 for my device. I'm constantly getting the iPad going into restore and then iTunes says my "device isn't eligible for the requested build". Is this a hosts file problem? What am I missing? Thanks in advance for any tips.