AMD Motherboards - 4x4 4800U BIOS error B4 with USB hub

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4x4 4800U BIOS error B4 with USB hub

Printed From: ASRock.com
Category: Technical Support
Forum Name: AMD Motherboards
Forum Description: Question about ASRock AMD motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=19386
Printed Date: 08 Aug 2025 at 11:48am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: 4x4 4800U BIOS error B4 with USB hub

Posted By: Mike4800U
Subject: 4x4 4800U BIOS error B4 with USB hub
Date Posted: 12 Aug 2021 at 1:16am

Hello,

I purchased an Asrock 4x4 4800U barebone some days ago. It is
now equipped with 64 GB RAM. It works fine with Ubuntu 20.04.

To save USB ports and more simply share keyboard and mouse
with another computer, I tried to use the USB hub in the monitor
(HP w2558hc). When I plugged in the hub, the keyboard and mouse,
all is ok.

When rebooting, the BIOS now stops with B4 error. It is not
possible to enter the BIOS setup anymore. To boot, I have to
plug off the USB cable and plug it in when the Linux boot is in
progress (or later on). Afterwards all is ok again.

The same happens, when the USB printer or a USB stick is attached.

The boot process works well, when I plugged in only keyboard and
mouse directly. It fails in other cases.

The printer is working fine, so I don't think its a problem of
the printer or the USB hardware of the 4800U. Same with the
monitor USB hub.

The BIOS is UEFI P1.30 of 11/27/2020 10:18:42.

What can I check to isolate the problem?

Best regards
Mike4800U