Apologies for taking so long to return to this thread, it took way longer than expected to get to the machine and get it up and running again.
I also just updated the build to the latest 4.9.60.
Here is a download link to both binaries and src.rpm (download the kernel tarball from
kernel.org manually to build from src.rpm):
To recap - I am also running with Tianocore EFI chain-loaded from u-boot, and mainling 4.9.x boots just fine on it.
No need for disabling ACPI on the kernel command line, no need to run EFI firmware as a 1st stage boot loader, it just works.
Do feel free to try it - if that works for you but the distro supplied 4.5.x kernel doesn't, it seems reasonably conclusive that it is the CentOS kernel that is broken for this board.
I'd also be interested in learning whether you have any luck getting PCIe cards to work with it without problems - I haven't tried it since upgrading to 4.9.x, but certainly on 4.4.x mainline the machine used to reliably lock up as soon as the driver for the PCIe card loads.
Gordan