Spoiler alert: You aren't going to find it.

Don't waste your time looking for a deep dive PDF. The "Acer MG43M Manual" is a mirage. Instead, look for community forums about the Acer Aspire XC-600 or T3-715 —those are the computers that actually house this board.

Look for a two or three-pin header labeled or "CLR1" . It is usually located near the bottom right corner, next to the front audio header. There is no button. You have to move a jumper cap from pins 1-2 to 2-3 for ten seconds.

Have you wrestled with an Acer MG43M? Did you ever find the hidden BIOS menu? Let me know in the comments below.

The manual won't show you a photo of this. You just have to hunt for it with a flashlight. The MG43M is fine for a retro Windows 7 build or a basic office PC. It usually pairs with an Intel H61 or H67 chipset (check the large chip under the heatsink).