After a "hard" power on (plugged in for first time) the "CPU" QLED stays lit and the device hangs. If I reset it, the CPU check passes and the "Boot device" QLED stays lit, and the "American Megatrends" screen dumps me into the BIOS (I can't remember the exact wording, in essence "You've set something to a stupid value that is making the system unstable, fix it"). Closing the BIOS and triggering another reset goes back to the CPU failure state above. (Very occassionally it seems to stumble into a Win10 "Your boot device is unavailable" message.
The (2.5") SSD Boot device is detected in the BIOS, and at the top of the boot order.
The system was stable as of three days ago, with a GPU drawing extra power, but with the old BIOS version (I upgraded to try and get it to detect an M2 SSD).
Really I'm after things to try: Can I force downgrade the BIOS? How can I tell if I've knackered (or fix!) the boot device?
Things to note:
- I don't have a system speaker*
- I didn't save my BIOS settings before upgrading*
- I can't get the BIOS to downgrade - it says "Selected file is not a proper BIOS!"
- I have also spent ages building a windows recovery disk on an SD card in a reader - which a different laptop recognises but broken desktop BIOS doesn't "see" at all.
- I have tried wiping BIOS settings by shorting two pins (and by taking out the battery and shorting two pins) , it just sets the CPU fan to max and sits there like a brick, until I restart it again, then I'm back to the status above.
System
- Motherboard: ASUS Z170-A / BIOS was 0504, now 3802
- CPU: Core i5-6600
- RAM: Corsair-2666 DDR4, 2 * 4GB
- GPU: Removed - internal only
- PSU: Antec 650W
- Yes, I'm an idiot.
