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The BIOS That Wouldn't Show

[Monday, August 4, 2025] MOOD: DEBUGGING Windows
○ NOT REVIEWED

The BIOS That Wouldn’t Show

Date: 2025-08-04 Duration: About 30 minutes of key mashing Issue: Couldn’t see BIOS/POST screen on any monitor Root Cause: BIOS was displaying, just not where I was looking

The Setup

ASUS board with an i7-4790K. RTX 4070 Ti with four monitors connected. Logitech wireless keyboard plugged into the receiver.

Needed to get into BIOS. Standard stuff.

The Problem

Power on. Black screens. Immediately start mashing Delete. F2. Delete again. F12 for good measure.

Black screens for about 3 seconds. Then Windows logo.

Tried again. Rapid-fire Delete the moment power button was pressed.

Same thing. Straight to Windows.

The First Theory

Wireless keyboard. Classic issue. Even though it’s technically “wired” (receiver plugged in), the USB stack doesn’t initialize fast enough for the keyboard to register during POST.

Tried shutdown /r /fw /t 0 from Command Prompt to force a restart into firmware.

Boot to firmware UI is not supported by this system's firmware.(1)

The 4790K era predates UEFI firmware commands. System is running legacy BIOS. That trick won’t work.

The “What If” Moment

Four monitors. RTX 4070 Ti. But the 4790K also has Intel HD Graphics 4600.

What if BIOS was displaying… but on the wrong output?

The Realization

BIOS doesn’t care about your Windows display configuration. It initializes whatever output it feels like using:

  • Sometimes the first detected GPU port
  • Sometimes integrated graphics (motherboard HDMI/DisplayPort)
  • Sometimes the “primary” monitor, which isn’t necessarily the one you’re staring at

With four monitors connected to a 4070 Ti, BIOS might have been:

  • Displaying on monitor 3 while I was watching monitor 1
  • Outputting to integrated graphics (which I had nothing connected to)
  • Using a resolution my monitors didn’t auto-detect

I was probably hitting F2 successfully the whole time. BIOS was loading. Just not anywhere I could see it.

The Fix

Option 1: Connect one monitor to the motherboard’s video output (HDMI/DVI/VGA on the I/O panel). BIOS often defaults to integrated graphics.

Option 2: Disconnect three of the four monitors. Use only one GPU output during BIOS access.

Option 3: Check all four monitors during boot. The BIOS POST might appear on a different screen than expected.

I went with option 3 first — just looked at the other monitors during boot. Sure enough, BIOS splash was on monitor 2 (my secondary), not monitor 1 (my primary).

The Lessons

Wireless keyboards during POST are sketchy. The USB stack might not initialize the receiver fast enough. Use a wired keyboard if you’re having timing issues.

Multi-monitor setups confuse BIOS. Windows knows which monitor is “primary.” BIOS doesn’t care. It picks an output and goes with it.

Integrated graphics might be active. Even with a dedicated GPU, motherboard video outputs can be enabled. BIOS might default to them.

You might be pressing the right key. If the system boots straight to Windows, you might not have keyboard problems. You might have display problems.

The Quick Reference

For ASUS boards with 4790K era hardware:

  • BIOS key: F2 or Delete (rapid tap from power-on)
  • Boot menu: F8
  • Not UEFI: So shutdown /r /fw won’t work

For multi-monitor debugging:

  • Try integrated graphics first
  • Disconnect all but one monitor
  • Check all connected displays during boot

Four monitors. One BIOS screen. It was there the whole time — I was just looking in the wrong place.