A lot of systems use fairly off-the-shelf bioses, that have lots of tools available for them that were intended for OEMs to do the minor, annoying tweaks that y

A lot of systems use fairly off-the-shelf bioses, that have lots of tools available for them that were intended for OEMs to do the minor, annoying tweaks that you described. There are sites [1] that specialize in discussing and using these sorts of tools. I had a lenovo laptop that behaved a lot like that, and was going to use a modded bios to fix it, but discovered that an updated bios actually had a bug in the halt code, so it would claim to halt, but five seconds later would continue the boot process. [1] https://www.bios-mods.com/downloads/ https://www.bios-mods.com/downloads/