I tried to restore my iPod touch4 but iTunes shows "This device isn't eligible for requested build" so what can I do ?

I tried this way to set up hosts and restart my Mac but when I going to restore my iPod touch4 ,it still shows "This device isn't eligible for requested build"

Thanks for replied me

if anyone has same problem to open their hosts file,here is a short video and you have to type "sudo nano /private/etc/hosts" ,not "sudo nano/private/etc/hosts",remember there is a space between "nano_/private"

This video helps a lot which I just found and it is much easier to fix this problem

https://www.youtube.com/watch?v=yHb1vdU6ReM