Two items re: the ASUS EX4 AIC I learned:
1. the 'firmware' update provided by ASUS for this card updates the Cypress chip but not the TB firmware
2. look at the serial number on the card; SN that starts with 'N' has correct firmware, SN that starts with '
M' never worked for me
3. If you have an EX4 card with SN that starts with 'M' I would see if I could return it to the store you bought it from; if not RMA the card back to ASUS
I hope this helps others. After multiple months waiting for ASUS to provide me with a solution, I tried something new. I figured I am most likely not getting this "custom bridge" BIOS version (and if I do it is going to take very very long). Thanks to some of the folks on this thread commenting on the ThunderboltEX 4 firmware possibly being incompatible with the new BIOS versions. I had firmware version 24 and I decided to just buy a new ThunderboltEX 4 with hopefully a higher firmware version. I was lucky and the one I purchased was firmware version 31. I'm not entirely sure if this was the sole reason for this but this new ThunderboltEX that had a higher firmware works on BIOS version 2004. I'm not planning on updating the BIOS from now on unless I really need to and something is not working. This serves asa lesson lol.
I hope this helps any of you in a similar position. I can finally get back to work.
I think the firmware level is the reason.
I would bet that the prior FW24 has the letter 'M' at the start of the Serial Number.
The card with FW32 has the letter 'N'.
I worked thru this issue with Asus quite a bit, one, the let them know what I found regarding SN correlation to FW. Also to let them know that what they have for download on the EX4 is labeled a FW update but that is only for the Cypress chip, not the Thunderbolt FW.
It seems Asus is not able to produce a TB FW update to take a FW24 to FW32.
Hello - Did you get anywhere with this? I ask - because I'm having issues with a Maximus XIII Hero board. Technical Support is working on a new BIOS firmware. However the version 1801 just release changed nothing for me. Curious to hear what experiences others are having.
The Firmware on the card itself is the issue, not the MB BIOS.
Look at the SN of the card on the box and see what I wrote above.
If you can, the real solution would be to obtain the updated firmware on the card by getting on labeled with the correct SN prefix (that is the letter 'N' is FW 31 and 'M' is FW 24 which doesn't work)
Hope this helps