[coreboot] Power button only works once - where to check for fixes (51nb X2100)?

[Rafael Send]

Hi,
As folks may have gathered from my other question about the GCC build
environment, I've been playing around with the old X2100 port (
https://github.com/mjg59/coreboot/tree/x2100_ng).

I got it to build and added the latest version of MrChromebox's Tianocore,
but there's still one issue that keep is from being very useable.

After flashing / plugging in the machine, the power button will turn it on,
but only once. If I shut down any OS, or even if it goes to sleep or
suspends, the power button no longer has any effect so the only "fix" is
currently to unplug power and re-plug it.

Where might I look for causes of this? Is it a shutdown state thing? ACPI?

Thanks,
Rafael