[Success] Z370M Plus II - Fix Shutdown Issue - Opencore

[NZRichard]

An old issue returned when upgrading from Catalina/Clover r5119 to Big Sur/OC 0.7.9 on a Z370M Plus II board - Signature/300 Series-3 - this board is a Z370M Plus II, not a TUF Z370-PLUS Gaming (closest option).

(The Z370M Plus II board was mainly sold outside the U.S. and maybe on e**y)

This issue may apply to other Z370 boards - the system does not fully shutdown (power LED light stays on) on shutdown.

Clover
In Clover there is a simply "FixShutdown" key that can be set to True and worked well on this board:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>ACPI</key>
<dict>
<key>DSDT</key>
<dict>
...
<key>Fixes</key>
<dict>
...

<key>FixShutdown</key>
<false -> true/>
...
</dict>
</dict>
....
</dict>
</plist>

Opencore

Dortania provides a fix for Opencore - https://dortania.github.io/OpenCore-Post-Install/usb/misc/shutdown.html - which provides patches for a missing s5 call - and a clue.

In BIOS the S4 and/or S5 calls can be enabled/disabled under APM/ErP (power settings):

1. Loading Optimized Defaults - disables ErP - shutdown seems to work on other Z370 boards, but not this one, or

2. Enable S5

3. Enable S4 + S5 - fixes shutdown issue for this board

That every problem could be fixed so easily!