works on MSI B450M Mortar Max
It works acceptable in my case (MSI B450M Mortar Max): I lost all USB 3.2 Gen1 ports on the back (directly on the mainboard) but the one USB 3.2 Gen2 Type A is working including all USB2 ports and all ports integrated in the case (1xUSB2 2xUSB3).
I put all drivers (AMD chip sets and so on) onto a second data disc, that I connected to the system (SATA) and installed all necessary drivers from there. So with an standard boot-USB-stick (prepared for Win7 with the MSI tools and the USB3 driver) and a PS/2 mouse everything worked much better than feared. Knowing that would have saved me much research time and head aches.