@aerith Hi and welcome to Win-RAID forums.
None of the BIOS I have modified for the Z370 Classified K have Xeon support but it can be added using CoffeeTime v0.99.
The ME firmware needs to be swapped for a corporate version (supplied with CoffeeTime) and then the Management Engine needs to be set to disabled.
Here is the latest modified 1.19 BIOS with ME corporate 11.8.95.4551_COR_H_DA_PRD_RGN_Cut and ME disabled.
1E379119_mod3_xeon.zip [Edit] file removed use dsanke’s BIOS
I will tag @dsanke just to be sure that I have not missed something, as he has actual experience with running Xeons (thanks in advance).
This motherboard has dual BIOS so if the BIOS does not work for any reason you should be able to recover by booting from the second BIOS chip, switching the BIOS chip to the ‘bad’ BIOS and flashing it again with a working BIOS.