Necessity is the mother of discovery, and I just needed to set up some Pololu USB-to-Serial adapters on my boss' brand new 64-bit Windows 7 Home Premium laptop. Neither hacking at Windows registry settings to permanently suspend driver signature enforcement nor manually booting without enforcement every time were ideal solutions, but I discovered that Silicon Labs has a signed CP210x driver available on their site, and you can force Windows 7 (and I assume Vista as well) to use these drivers without changing the VID/PID of the adapter. I have only tried this with the Pololu USB-to-serial adapters so far, but it should work with any device based on a SI CP210x chip:
Download and install "CP210x VCP Windows 7 Drivers" from Silicon Labs here.
Plug in your Pololu USB-to-Serial Adapter (or other device that uses a SI CP210x USB-serial adapter chip). You will see an error message that the device was not properly installed.
Load the device manager from the control panel, find the adapter listed under "Other Devices", right click on it and go to "Properties"->"Update Driver"
Select "Browse my computer for driver software", then "Let me pick from a list of drivers on my computer"
Select "Show All Devices" then click "Next"
Follow 6A or 6B:
6A. Wait for the driver list to finish populating, then select "Silicon Laboratories" as the manufacturer and "Silicon Labs CP210x to UART Bridge" as the device, then click next.
6B. If you get tired of waiting for your computer to generate a list of drivers, click "Have Disk" then "Browse", and select to "c:\SiLabs\MCU\CP210x\Windows_7\slabvcp.inf", then select "Open", "OK", then next.
- Click "Yes" to get past the "Update Driver Warning", then close the success window.
Take that Windows 7!