Hi,
I too have an urgent need to disable XHCI via the BIOS.
This was a feature that was present in previous BIOS's but was removed for no apparent reason.
From the release notes for BIOS version 0025:
Removed [USB3.0 (XHCI mode) support] option from BIOS Setup and
enabled it by default.
Please can this be added back to the next BIOS ?
I have tried doing this a number of ways via software but cannot achieve it.
Thanks