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Beware USB3 PCIe and hubs!

Level 7
From my FB post on the problem, in the interest of helping someone who has a similar problem. Browsing this Forum helped me solve the issues.

The system was working great, except that I could not enter the bios on boot.

Googling around seemed to indicate its a power setting problem - fast boot enabled. Turning that off had no effect. Replacing bluetooth keyboard with wired USB keyboard had no effect. Further googling indicated one guy recovered from this by removing the BIOS battery and reinserting it. Fixed the problem! Only then the machine would just end up in bios and not go to windows. Further googling on this forum showed someone had exactly my problem and fixed it by unplugging the power USB hub. Lo and behold, unplugging the powered USB hub, fixed the original problem! (which was really that it couldn't detect a keyboard.) However, now I could only boot into bios and it would not boot windows.

Well it turns out removing the bios battery reset the bios (as it should), but that reset also enables secure boot keys and disabled CMS booting. Another google exercise on this forum. None of the computer devices showed up in the boot sequence option menu at all. Only after turning off secure boot and enabling CMS boot (legacy booting) could I recover windows.

It turns out that the expansion USB powered hub is only a problem if plugged into the PCIe card with USB3 ports. When I plug it into a USB3 port on the MB I can get into the bios during boot, no problem. Who would know such a thing? The problem lies with the technical interface between the PCIe board maker and the MB maker. Technical interfaces are where most technical problems arise, because no one takes responsibility for a fix.

Also since then have found further squirreliness. If a powered USB3 backup drive is plugged into one of the USB3 ports on the MB, the USB3 powered hub in the other port has to be unplugged for the MB to detect the keyboard.

Hopes this helps people, who like me, had no clue why things went south.