Root Trouble updating radio

[sk8skanj]

So I'm currently at stock after using PB31IMG to unroot and am now trying to update the radio to 2.05 so I can flash SkyRaider 2.2

Anytime I try and run the update in recovery I get the error message...

E:Can't open /cache/recovery/command (this comes up before even trying to run the update)

--Install From sdcard...
Finding update package...
Opening update package...
Verifying update package...
E:signature verification failed
Installation aborted.

 

[fortesquieu]

Before you select the zip file, select "toggle signature verification on".

 

[sk8skanj]

isn't that an option clockwork only? the walkthrough I'm following says you need to be unrooted.