I have a Gigabyte Z390 Designare motherboard and it uses the latest Titan Ridge controller for the two native Thunderbolt 3 (USB-C type) ports. Currently, the newest Z390 Designare firmware doesn't offer a legacy compatibility mode like the Z370 boards, which had Alpine Ridge controllers, before.

I want to connect a Thunderbolt 1 audio interaface via Thunderbolt adapter to the Thundeerbolt 3 port on the Z390 Designare, but the Desginare's firmware doesn't interpret the Thunderbolt 1 signals correctly. Thunderbolt 2 devices do work with the adapter, it's just a Thunderbolt 1 compatibility problem. I found a possible solution for this problem, but the Z390 doesn't have this BIOS entry in the Thunderbolt menu.

Since I never modded BIOS, I need to know if it's even possible in the first place to add Thunderbolt (TM) Enumeration mode to the Z390 BIOS so that it can be set to "Bios Enumeration / Legacy" instead of "Native"?

I alredy contacted Gigabyte and they've acknowledged this issue. They had a working internal firmware which wasn't approved by Intel themselves, as they don't want to include the legacy mode for the Titan Ridge controllers. Since they can't do it officially, maybe there's a way to modify it unofficially and make it work that way, without Intel's approval...

@Lumberjack - Lets see if we can fix this for you. Please show me BIOS images of all sections you can see Thunderbolt settings in, this way I can see what's visible to you, and then enable what you can't see.
I see TB settings at Peripherals >> Thunderbolt(TM) Configuration (Also a submenu here >> Discrete Thunderbolt(TM) Configuration with three additional submenus inside there too)
None look to be specifically what you asked about, but I'm not familiar with TB, so it could be named something different and I don't recognize it.

Also, for my own comparison, please give me a Z370 model you know of from Gigabyte with the options you wanted.

@Lost_N_BIOS The Z370 mobo is the Gigabyte Aorus Gaming 7. Here are the BIOS download links:

https://www.gigabyte.com/Motherboard/Z37...support-dl-bios

F11 included the GC Alpine Ridge card support.

And here's the BIOS page for the Z390 Designare:

https://www.gigabyte.com/Motherboard/Z39...support-dl-bios

I don't know if this is possible, since one system uses a PCI-E Thunderbolt 3 card with Alpine Ridge controllers and my system has native Titan Ridge controllers for the two Thunderbolt 3 ports. Maybe the Bios Enumeration menu is deliberately hidden in the Z390 Designare since it can fry the controllers?

EDIT: Here are some BIOS screenshot of my Z390 Designare's Thunderbolt settings:

https://bit.ly/2H2JFZi

https://bit.ly/2XHzoH0

I already have all BIOS, just needed to know which had what you wanted. No, I checked before I replied, nothing like that hidden.
I will see what I can do, but yes, even if I could get the settings transferred over, it may not work due to different type of controllers and TB has it's own onboard FW too I think (like EC FW)

Do you have a flash programmer like CH341A and SOIC8 test clip cable? Or does this board have BIOS switches where you can set single BIOS or dual BIOS, and or switch between main and backup BIOS manually?
Dual BIOS recovery is not what I'm asking about here and it wont save you in testing things like we're discussing if things go wrong.

Unfortunately with your motherboard (F6 BIOS) I cannot find any trace of such option in the ROM I downloaded from the Gigabyte website.

I looked with AMIBCP5020023 and by extracting IFRs.

Normally there are two ways. Download AMIBCP5020023 and open BIOS, enable all Thunderbolt options, save and flash.

Otherwise you can extract IFRs from setup, and use the information to use an EFI shell to change the hidden variables.

You can download the EFI shell onto a USB and temporarily disable Secure Boot to run it. Command is "setup_var <offset>" to view value and "setup_var <offset> <new_value>" to set.

Anyways, since there is no hidden option (not sure why, perhaps in the latest Thunderbolt BIOS revision it was dropped) we need to address what is wrong with the adapter. Can you provide more information? Is this Windows or Linux? If you download PCI Utils for Windows (or included in most Linux distros) and as admin do "lspci -xxxx" when problem is encountered and post the output then it could help.

@Karatekid430 I'm having the same hardware scenario as well.
Has this been revisited at all? I know it's a year old....
This is windows 10 and the adapter is a Thunderbolt 1 card for a universal audio interface. The interface has a card slot that originally took a FW 800 card, then the company provided a Thunderbolt 1 card, then almost immediately started selling the interfaces with thunderbolt 2 cards and most recently you can put in a thunderbolt 3 card.

So if you're getting a z390 board, which comes highly recommended for this interface, you have to purchase a thunderbolt 2 or 3 card @ $500+.
It's possible that this is the solution....
Thanks for any insight!