P67 Extreme 4 Code B4

[aguerrero84]

Hello,

First time user and I'm having an issue. I am using bios 1.7. Occasionally, upon reboot, the PC will hang at the POST screen with a b4 code on the Dr. Debug LED. According to the manual, this has something to do with USB.

I have found this to occur much more frequently if I have any storage device connected to the USB 2.0 ports (~50% I'd guess). Unplugging the device will sometimes get it to continue to boot, but not always. Less frequently, I'll get the same code with no storage devices connected. I have a USB keyboard, mouse, and printer.

I have found that disabling Legacy USB or setting the same setting it to "UEFI setup only" will prevent it from cycling through the b4 code entirely and while this is a solution, I am still concerned that something may be wrong.

I have tried multiple bios versions with the same thing happening. Has anyone experienced this problem? Any idea what could be causing this?

Thanks very much,
Adam

[aguerrero84]

After further investigation, I believe this is simply a hardware incompatibility issue with the UEFI.

I have three USB devices connected: a MS sidewinder mouse, MS keyboard, and HP printer. The mouse has had some weird behavior in legacy mode when it does decide to work. So I suspect that might not be completely compatible.

But my sansa clip with 16gb microsd (shows as two hdd's in UEFI) seems to create the "b4" no post problem nearly every time.

At the very least, changing legacy usb to "UEFI only" seems to fix it, while still giving me access to BIOS.

Unless someone else can think of something?