Upgrade Air ios8.4 to ios9 (jailbroken)

[Steve-Jobs]

Hi, I installed the custom ios9 ipsw and tried to install it to my jailbroken ios 8.4 iPad Air. I got an error saying the device is not eligible for the request build.
I really don't want to lose my jailbreak and upgrade is there a way to save it and find the correct ipsw?

Cheers

EDIT: I'm still on Yosemite so my itunes is not updated either. if that helps...

 

[Steve-Jobs]

I just updated my itunes but still getting the same error, even tried a different wifi network.

 

[Steve-Jobs]

Can someone please help me with this. Cheers