@CaseySJ I messed around the bios settings with setup_var_3, and it seems the egpu is sort of detected with hotplug (with an unknown device); however, the egpu is still not worked. (PCI detects nothing in System Information app except the Alpha Ridge chip; Nvidia driver is not loaded) With coldboot, the results is still the same and worse with these bios settings - nothing is shown in the thunderbolt bus. I attached the ioregs. (It seems nothing changed.) Do you think I should use these bios settings with your mod1? I am curious what you changed in those mods.
View attachment 492854
I'm trying the following bios setup with setup_var_3:
Titan Ridge Workaround for OSUP 0x513 Enabled 0x1
Security Level 0x4F3 No Security 0x0
Current Security Level 0x127B No Security 0x0
SW SMI on TBT hot-plug 0x4F5 Enabled 0x1
ACPI Notify on TBT Hot-plug 0x4F7 Enabled 0x1
GPIO3 Force Pwr 0x4F0 Enabled 0x1
Enable TBT ASPM 0x514 L1.1 & L1.2 0X3
Windows 10 Thunderbolt support 0x512 Enable + RTD3 0X2