The company I work for has a product with a USB Device port implementing the CDC class. Our driver is based on Microsoft's
USBSER.SYS driver and we provide the specific INF files so that our product installs as a virtual COM port. It works well on Windows XP, Vista and Windows 7 32-bit & 64-bit versions.
We need them to test in Windows 7 Embedded standard 32-bit and 64-bit OS. But there is no USBSER.SYS file in both the OS. We read some forum and found to use the Windows 7 Ultimate (32-bit) OS, usbser.sys (with our INF file) in Windows 7 Embedded standard
32-bit OS and it worked properly. And we tried to use the Windows 7 Ultimate (64-bit), usbser.sys file (with our INF file) in Windows 7 Embedded Standard 64-bit OS, but it showed error message like “Driver does not contain digital signature information”.
For testing purpose, in Windows 7 Embedded Standard 64bit OS, while booting we pressed F8 and selected "Disable driver signature enforcement" to disable the signature checking process and updated the driver properly. After restart the system without pressing
F8, It shows the following error message:
“Windows cannot verify the digital signature for the drivers required for this device. A recent hardware or software change might have installed a file that is signed incorrectly or damage, or that might be malicious software from an unknown source.
And in “Driver File Details” tab, it shows the Digital Signer as “Not digitally signed”.
USBSER.SYS driver file is belonging to the Microsoft, and then why it need to digitally sign the driver file?
Could anyone help us, what is missing to run this INF successfully for Windows 7 Embedded Standard 64-bit OS?