Upgrade iPhone 5 from iOS 7.0.4 to iOS 7.1.2 [duplicate]

I have an iPhone 5 that I use with Straight Talk (telecom provider) and I am trying to "upgrade" it from 7.0.4 to 7.1.2, or any release with the 7.x version for that matter.

I specifically do not want to upgrade to IOS 8 just yet.

I have the file "iPhone5,2_7.1.2_11D257_Restore.ipsw" but I get the error "The device isn't eligible for the requested build." I've also hashed out the gs.apple address in my hosts file.

I know you can't downgrade from 8 to 7, but in this case is there a way I can still upgrade to a later version of 7.x?

Apple have stopped signing any iOS 7 for any device that can run iOS 8.

As far as I am aware, you have no other choices than to stay on 7.0.4 or go to 8.0.2