Downgrade iPhone 4 6.1.3 to 6.1.2 for untethered jailbreak?

[Solidarity]

Hello,

Just wondering if it's possible to downgrade my iPhone 4 from the current 6.1.3 firmware to 6.1.2 so I can perform an untethered jailbreak?

I purchased my device already updated to 6.1.3 and I've been waiting 2 months for an official untethered but it hasn't arrived (and probably won't be arriving until IOS 7 so Apple doesn't patch any 6.1.3 exploits in the next update).

Thanks

 

[NewYorkInc]

redsnow can downgrade a iphone 4 it you have the shsh blobs saved