Boot hangs without monitor attached?

[curaga]

Good to see you solved it.

re #26:  Too bad there aren't "anti-switches" for the linux command line that counteract other switches on the command line.     (I know, security nightmare!)  If they existed, then one could still use a stock distro to debug by re-enabling boot time messages.

Actually, you can, they exist

Anything later on the command line overrides the previous one. So "quiet debug" would use the latter, and print a lot of kernel messages.

[Rich]

Hi curaga
I was not aware of that, thank you.

[gerald_clark]

You should complain to the manufacturer and request a BIOS update.