I've spent a few hours flashing and then checking 4* GC-Titan Ridge controllers (for future builds) last Thursday.
All 4 flashed w/o issues.
All 4 worked on Windows.
But only 2 worked on macOS:banghead::crazy:.
Then I noticed (Thunderbolt software panel on Windows) that non-working on...
"Current NVM version = 26" means that you have the ThundeboltEX 3 with 15D2 chip version.
The chip1_Fw.dat file is for 1577 chip version.
15D2 requires the chip2_Fw.dat file that is missed in the zip on the ASUS site.
I have two new ThundeboltEX 3 controllers (for the upcoming builds) both...
I've checked it and there are no any signs of HS07/08 presented. There are no signs of HS07/08 even in USB Single Port Control in BIOS.
Also, I've just done USB kext for ASUS Z170-A and it has the same story - there are no HS07/08 ports.
Here are all files. I've disabled USB3_34 header.
1. As I said in the original post: iMac18,1 and iMac18,3 SMBIOS in the files.
3. Yep, on 10.13.6 I did discovery according to your manual. Here is the result.
There are two Aura connectors on the M/B, so HS07/08 might be assigned to them, but I can't check it.