[gentoo-user] sysrescue+new asus mobo+secure boot=0

[John Blinka]

Hello, Gentooers,

I just acquired a new Asus board (b560m tuf gaming+wifi) to replace a
failed gigabyte board on my main Gentoo machine.  Assembly went well, it
powered up flawlessly first time, it recognized all the hardware... and
then nothing.   Cannot get it to boot.

On all my other machines, there’s a bios setting that allows me to turn off
secure boot, which allows me to boot Sysrescue from usb, or Gentoo from a
hard drive.

Not so (as far as I can tell) on this mobo/bios.  There’s the usual bios
boot menu and a secure boot submenu.  However, the secure boot submenu only
allows me to select between Windows UEFI (with, presumably, secure boot
enabled) and “other OS”.  I have no clue what “other OS” implies about
secure boot.  It also offers the ability to accept the standard
Microsoft-supplied secure boot keys, or to change or delete them.  There
are a few claims on the web that clearing the PK key (and only that key) or
clearing all of the keys is the way to turn off secure boot.   I’ve tried
all the combinations; none of them allow me to boot.

The farthest I’ve gotten is to display the Sysrescue usb boot choices.
Selecting any of them seems to (briefly, for a second) start a boot and
then the screen goes blank.  Nothing after that.

I haven’t found any mention on the web that Asus boards are particularly
linux hostile, nor much discussion implying that turning off secure boot is
particularly tricky.  Most of what I’ve seen is, say, Ubuntu oriented.  I
gather that they have gone through the process of getting their secure boot
keys authorized by Microsoft.

Anybody have success getting Gentoo to boot from a recent Asus mobo?

Thanks!

John Blinka