Laptop won't boot with certain usb devices plugged in

[Hank___]

Upon power-up, when a USB-C to hdmi adapter and a USB-A hub are plugged in, the laptop turns on but only shows a blank screen and after some time the caps lock key blinks 5 long then 4 short flashes.

Looked up what this means and the error description is as follows:

"Embedded controller times out waiting for BIOS to return from system board intialisation (end of POST)"

I have tried the following:

• Hard restart
• Disable USB boot in BIOS
• Update BIOS to latest version

None of these have helped, and the laptop boots just fine with a USB AMP-DAC plugged in.

[WAWood]

@Hank___ 

I have a similar problem with my HP laptop -- as any device connected to a USB port like a hub or drive, the PC will attempt to boot from it AUTOMATICALLY, no matter what I do.  I have to disconnect those and reboot.

My guess is it is the USB hub.

If you can boot OK without it connected, then that is what you will have to do.

There is no way around this.