OC 0.6.4 stuck with Dualboot macOS/Windows

[hausi]

Hi guys,
any new insights related to multiboot ?
I have been fighting with multiboot from OC (between macOS 11.1 and Windows 10) for a couple of days now.... reading several posts/threads/guides.

1st: Big Sur on my hack is working fine/perfect (on a Gigabyte Z390 Aorus Pro & 5700XT).
Then I tried:

• had Windows clean installed on a separate SSD (M.2 NVMe); booting via OC-picker (or boot priority in BIOS) which always results in error code "0x0000001" or stop code "ACPI_BIOS_ERROR"
  Now another attempt: I reinstalled Windows following exactly this Opencore Dualboot Guide - did a fresh reinstall of Windows 10 on a separate SSD + added the entry for Windows into Misc --> Boot --> Entries
  Result: I can boot macOS, I can see Windows in the picker --> booting Windows results in "ACPI_BIOS_ERROR"
  
  
• another try: Followed the steps described by "dorintia" (https://dortania.github.io/OpenCore-Post-Install/multiboot/bootstrap.html) - with the result, that I could switch (using Startup Disk), boot into Windows worked with no errors. But I never could switch back to macOS (Installed Boot Camp utility on Windows, selecting macOS as Startup Disk didn't work - always boots back into Windows)
  --> the only way out of this (and boot macOS again) is to reset CMOS of my motherboard

My questions:

• How did you do it ? Who succeeded ? - using Boot Camp ?
• OpenCore parameter or settings that prevent Windows to smear something into NVRAM ?
  What are the most critical OC parameter to secure OC/macOS NVRAM entries ?
  YES: Windows modifies entries - on one of the restarts I had the hostname Windows gave my PC (DESKTOP-xxx) as the hostname in macOS.....

I hope my perception to have a flawless dual-boot between macOs and Windows using OC is not an illusion....

Thanks for your advise! - A pointer to a working Guide is appreciated!
regards
Hausi

 

[dfritchie]

What I do:

Remove all drives except windows drive
install windows
remove all drives except macOS drive
install macOS
install all drives
use bios to select which os to boot

works every time.

 

[hausi]

Thanks - will try (again).
To be honest: When I remember the tons of attempts correctly - booting Windows thru BIOS did work (no errors). But going back to OpenCore/macOS was the problem. I had the situation where OC did nothing (booting with "-v"): Did not print a single line, just went back to the picker (after a couple of seconds).
Clear NVRAM/Reset NVRAM (from OC picker) did not help.

What's the best way to preserve OC's settings/NVRAM entries ?

best regards & merry Xmas
Hausi

 

[hausi]

Success:
- I did set a couple of OC parameters (according to guides/posts)
- I can boot Windows from BIOS (boot priority) - I cannot select Windows from the picker (still gives ACPI_ERROR) and I did not touch Boot Camp
- had to change OpenCore as #1 in boot list (BIOS) once - now its stable, and boots into MacOS

regards
Hausi

 

[dfritchie]

Good deal

 

[hausi]

Thanks for your reply.
FYI: CleanMyMac detected a "XCAssets Backdoor" in your attached dmg....

Regards
Hausi

 

[UtterDisbelief]

Thanks for your reply.
FYI: CleanMyMac detected a "XCAssets Backdoor" in your attached dmg....

Regards
Hausi

Hi there.

I've removed the post you mentioned for checking. Thanks.