Thunderbolt issues (Z390 Aorus Pro Wifi with flashed Titan Ridge v2, OpenCore)

Hi,

Issue in shortThis build has been functioning quite well since januari but has ongoing thunderbolt issues. Occasionally devices will not be recognised at all, but mainly the problem is that some devices are recognised, but not all of them. This mainly happens with Apollo audio interfaces.

• The hardware:
  • Gigabyte Z390 Aorus Pro Wifi
  • i9 9900K- Radeon 5500XT
  • 2TB XPG 8200 Pro
  • 64GB DDR4
  • Gigabyte Titan Ridge v2 (flashed)
  • UAD Apollo Quad (thunderbolt 2)
  • UAD 2 Satellite Octo (Thunderbolt 2)
  • UAD Apollo X16 (Thunderbolt 3)
  • UAD 2 Satellite Octo (Thunderbolt 3)
• The software:
  • Opencore (tried 6.4 and 6.8)
  • I have flashed the Titan Ridge card, hotplugging functions but not always
  • macOS 10.15

The issue: So, I've built this machine for a friend who is a music producer. Things were fairly okay when he was only using the Apollo Quad and Apollo X16. Problems really started when he expanded his gear with two UAD Satellites. The four devices are dais chained on the Thunderbolt AIC. In all possible combinations of daisy chaining, no more than three devices will be recognised at a time (and often only two).

From the start, Thunderbolt has not always been recognised properly. Under System Information > Thunderbolt, sometimes it will show Thunderbolt info as on a real Mac: the separate busses, with a tree structure of what's connected. Sometimes however it will only show "Thunderbolt Bus:" with a vendor name (Gigabyte), Device name (iMac) and Domain UUID.

What I've tried: A lot. I've troubleshooting extensively, searching and following a lot of guides, tried two different firmwares on the Titan Ridge card, two versions of OpenCore, a custom OpenCore install and a prebuilt for the same motherboard and Thunderbolt AIC and fresh macOS installs.

Really hopeful someone here can shed some light on the matter.