My Motherboard/BIOS doesn't detect USB devices (Mouse, Keyboard) when I cold boot my computer (booting after complete shutdown). BIOS is always showing me 0 Keyboard / 0 Mouse / 2 USB Hosts connected. If I press the reset button at that point, my computer reboots and BIOS will recognize all devices. Fastboot is OFF.

This means that I have to press the reset button on my computer after every cold boot. I can't figure out what's causing this

  • If I don't press the reset button during first boot and let my PC continue to boot with 0 Mouse / 0 Keyboard detected, they will NOT be detected by the operating system either (Ubuntu, Windows 10, Hackintosh).
  • BIOS recognizes that 2 USB Hosts are connected (front panel USB Ports on my Case)
  • The LEDs of my Keyboard and Mouse stay off when they are not detected by BIOS (they don't get any power at all).
  • The problem persists regardless of which Keyboard, Mouse or USB Port I use (Apple Keyboard, WASD Keyboard, Corsair K65 Keyboard, Logitech MX 518 & G502 Mouse)

I'm using the following BIOS Settings potentially relevant to USB:

  • Fastboot: Disabled

  • POST Report: 5 Sec

  • Boot up NumLock State: Enabled
  • Interrupt 19 Capture
  • Legacy USB Support: AUTO
  • Intel xHCI Mode: Smart Auto
  • EHCI Hand-off: Disabled
  • Launch CSM: Enabled
  • Boot device control: UEFI and Legacy OPROM
  • Boot from storage devices: Legacy OPROM first

Hardware: Asus Maximus VII Hero (Z97, BIOS Version 3201 x64), Intel 4790K, 32GB RAM, GTX 1080

  • In most cases I have seen you had to mess about with the Intel xHCI Mode and the EHCI Hand-off. Some combinations just don't work. Be advised that changing these may affect how your OS detects the USB devices. – Tonny May 30 '18 at 13:48
  • Thanks, I think I solved my problem following your comment (see my Answer below). I think this was caused by a combination of things, namely EHCI Hand-off, but also Auto settings not working as they should. Lesson learned: don't trust "Auto settings. – karlo_asm May 30 '18 at 15:38

OK I think I've found a solution following Tonnys comment. Hopefully this will help someone with the same issue. Read carefully so you don't have to reset your CMOS like I had to.

  1. I had to set EHCI Hand-off to Enabled,
  2. This is important: I also needed to change Legacy USB Support from Auto to Enabled.

I left Legacy USB Support set to Auto first, which caused my Motherboard to not detect USB Devices during boot AT ALL (not even after reset) and I was locked out of BIOS completely. I guess Auto doesn't work as it should. I had to clear my CMOS in order to be able to get back into BIOS.

  • Good job! If I remember correctly: EHCI Hand-off is a requirement for USB Legacy to work correctly. Some Bios will silently enable EHCI hand-off if USB legacy support is needed, while others need both settings to be explicitly set. – Tonny May 30 '18 at 15:50

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