I have been running cynangenmod 7.1 on an sd card for a couple months with my nook color. I run it from the sd card so I can take it out and go to the stock os when I want to. The new stock os (1.4) came out tonight and I downloaded it to my computer to load on my NC. I took the cm 7.1 sd card out of the nook. Every time I have tried to load the new os on the nook I get the droid robot, triangle and exclamation point a few seconds after the update starts to install. When I then push the power button the clockworkmod recovery screen shows up with its various options. Below the options are the update steps that started. They stop with the message: " E: failed to verify whole-file signature" and below that: "E: signature verification failed" and below that "Installation failed". By running CM 7.1 from my sd card, I was under the impression that when I took it out the stock os would work as did in the factory. It seems to me clockworkmod recovery has been found its way into the stock os. I have done several factory resets but always end up back at the same place; unable to install the new update with CWM showing up. Any ideas on how to fix this?