How can I open COM4: on iMX7 in WEC7

I want to use COM4 (UART_D) on the iMX7 in WEC7 in my C++ application. When I call CreateFile with “COM4:” as the parameter, an invalid handle is returned. The code is working fine for COM2: and COM3:.

I see that the registry has entries for COM1 through COM7 in HKLM/Drivers/BuiltIn.

What can I do to use that port?

Thanks so much for your support!!!

You need to edit

[HKEY_LOCAL_MACHINE\Drivers\BuiltIn\COM4]
    "Dll"="_serial_imx7.dll"

and remove leading underscore.

AH - it was right before my eyes!
Works just fine.
Thanks for being so fast to answer!

You are welcome.

Best regards,
Jaski