Thunderbolt Expansion Chassis problems

[BerndVP]

Hi,

I hope there are some smart people here who can try to figure out with me what is going wrong with my setup.

So I'm a professional Audio Mixing Engineer and I have a studio.
I'm using Avid Pro Tools Ultimate as my DAW along with an Avid HDX Card (DSP Based Audio PCIe 2.0 x4 card).

For a long time I used it direct in the system on a PCIe x8 slot, just working fine.
Earlier this year I found out it was possible to get Thunderbolt working on a MacPro with a Titan Ridge AIC.
So my older system that was an Z77X-UD5H system was the perfect system to try it out.

So after two days of try and error with the Titan Ridge Card and an 'Sonnet Echo III TB Expansion Chassis',
I figured out that when using an SSDT for HotPlug, the PCIe card [AVID HDX] was recognized in IORegistryExplorer, but the 'Client / Driver' won't connect.
When I disabled the SSDT for HotPlug, the 'Client / Driver' finds the card and connects it.
So for some reason with the SSDT the driver can't find the card, but if you look at the IOREG, the card has still the same DeviceID.

So, any smart people who can try to find a solution with me or get me in a direction I have to look.

I attached some screenshots from SSDT Injected, not injected and the TB Chassis connected to my MacBook Pro.

I switched over to an X299X system with onboard Thunderbolt and no flashed firmware, because I don't need it.
With SSDT injected, card not connecting, without SSDT, card connects