On boot I get the message:
ucsi_ccg 0-0008: Failed to get FW build
A search suggests it is trying to configure USB-C on a non-existent Nvidia GPU.
It is bugging me and I’d like to remove the cause of the error if possible. Any ideas what I could have configured that may cause this? Or is it just something that happens as part of the boot process?
You’ll want to add ucsi_ccg to boot.blacklistedKernelModules.
Didn’t check if that module actually does what you say it does. If this makes your usb type c ports not work, it’s not my fault 
It happens by default because that module is apparently part of the kernel package by default. Presumably because it’s commonly needed on consumer laptops. You could alternatively compile your own kernel for just the hardware you have, but that’s a fair bit of effort.
Thanks for the clarification it is in the default kernel (I haven’t dared to change given I don’t feel confident with the level of documentation I’ve seen).
I’m running a AMD 3900x (on X570) and 6900XT. I can confirm that blacklisting this module averts the error and speeds up boot slightly. The mobo USB-C and the GPU USB-C both work correctly, so Nvidia only seems plausible.