Please help with PRI downgrade!!

[njc4949]

I am having trouble downgrading the PRI on my EVO. I am using clockwork and I will boot into recovery and tell it to install the zip and it very quickly looks like it's working and then just goes back to the recovery screen. I reboot the phone and check the PRI and it is still the 1.90. I'm trying to go to 1.77 for the netarchy-toastmod kernel. Someone please give me some advice on what to do.