I have a backup of my phone with IOS 6.x on a Windows box. I can restore to it fine but I am unable to upgrade to 8.1.2 as opposed to 8.3 so I can jailbreak the phone again but with the newer IOS. I understand that 8.1.2 is no longer signed which is causing the issue. Is there any way to get 8.1.2 on this phone? Thank you!