facebook transparent twitter
Go Back  

SawFirst Forum

> SawFirst - About Your Virtual Presence > Windows / Mac / Android

Windows / Mac / Android Anything you need to know or let us know, post here.

Thread Tools
Old 06-03-2020, 11:39 AM
Pretty Girl's Avatar
Pretty Girl Pretty Girl is offline
Join Date: Jul 2019
Location: Manila
Posts: 1,542
Default Dual Boot macOS and Windows 10 from same SSD with OpenCore


(1) HD/SSD free to formatting

(2) Windows UEFI installer

(3) Working NVRAM (native or emulated) and also available to be cleaned

(4) Firmware UUID:
– Original hardware UUID. Necessary to avoid Windows activation problems
– To get this, type: wmic CsProduct Get UUID at Windows Command Prompt
– The result will look like 00000000-1111-2222-3333-444444444444

(5) OpenCore's config.plist edits:
– At Misc/BlessOverride add following String: \EFI\Microsoft\Boot\bootmgfw.efi
– At Misc/Boot, set HideSelf=NO and PollAppleHotKeys=YES
– At Misc/Security, set AllowNvramReset=YES. This allow's OC to reset NVRAM
– At Misc/Security, set AllowSetDefault=YES. This allow's OC set default boot option
– At PlatformInfo/Generic, replace SystemUUID from SMBIOS with Firmware UUID
– At UEFI/Drivers, add entry OpenUsbKbDxe.efi and add related file (found in OC's release) in folder EFI/OC/Drivers

(6) BootCamp software for Windows:
– See Additional Boot Camp Notes, please
– At macOS, insert a flash drive
– Open Disk Utility
– From the menu bar, select View/Show All Devices
– Select flash drive and format it as MS-DOS (FAT32), with Main Boot Record (MBR) scheme
– After that, run Boot Camp Assistant (in Applications)
– From the menu bar, select Action/Download Support Software for Windows, select flash drive as destination and wait for the entire process finish (it may take a while)
– TIP: I have a single 16GB usb with OpenCore, Windows installer and also Boot Camp software, so I can choose what start when I need. That save time when I'm looking pendrivers during installation process!


(1) Through OpenCore USB stick, boot into macOS installer.
– This is first time I've clean nvram

(2) Format entire disk as HFS+ with GUID scheme (REMEMBER: ALL DATA WILL BE LOST)
– Add two partitions, one for each system
– Format macOS's volume as APFS
– OPTIONAL: Format Windows's volume as ExFAT

(3) Start macOS installation
– At the end of 2nd stage, we can go to Windows

(4) Through Windows usb, boot installer
– Remove ExFat volume to create Windows's default partition
– An aditional partition, only 16MB – MSR (Reserved) – will be created automatically
– Start Windows installation

(5) Once Windows's full installation is finished, is time to back to macOS using OC usb
– Finish macOS installation
– Mount EFI partition
– Delete "Boot" folder and rename "Microsoft" folder (eg: Microsoft-bak)
– Add OpenCore folders: BOOT + OC

(6) Restart system and remove all/any pendrive
– Press BIOS boot key (F12 on Gigabyte) to check available boot options
– Probably there's two options: Windows Boot Manager and UEFI OS (HD). The first one boot, of course, only Windows and the second one boot OpenCore
– At this point I've cleaned NVRAM once more, first to remove "ghost" Windows Boot Manager option and second to make UEFI OS (HD) the default boot option

(7) Back into macOS (now through DISK)
– Restore renamed Microsoft's folder from EFI disk partition

(8) Restart system and let it boot automatically into OpenCore GUI
– At this point, Windows's partition is available to boot

(9) Start Windows through OpenCore
– Connect flash drive with Boot Camp installer
– From WindowsSupport\BootCamp, run Setup.exe
– Authorize instalation, click "Next", accept license terms and then click "Install"
– After succesfull instalation, system will restart automatically and when back to Windows, Boot Camp icon will be at Task Bar (next to clock)

(10) How Boot Camp works?
– It allows quick switching between macOS and Windows.
– When a system is chosen to boot from Boot Camp, that information is saved to NVRAM and this becomes the default boot option. Eg .: If, at Windows, I select "Restart on macOS…", every time I turn on PC, or macOS will already be selected at OC GUI, or will start automatically and same happens when Windows is selected at macOS's Preferences/Startup Disk.
– To make Boot Camp more dynamic, additional configuration in cofig.plist is required: or Misc/Boot/Timeout=5 or Misc/Boot/HidePicker=YES. In the first one a countdown will start and in the second one, OC GUI will not appear and selected system will start automatically. But still possible to choose manually a different system to boot, just hold down "Alt" key (or Windows key) until OpenCore GUI appears, hit Enter to boot only this time into desired system or CTRL+Enter to save this option as defult partition.

(11) Additional Boot Camp Notes
– The only big advantage of Boot Camp is the quick switching between systems, much like switching users. What means that, even w/o Boot Camp, still possible to choose which system to start from OpenCore GUI
– HFS+ or APFS disks probably will not be accessible in Windows until a third party program is used
– There's, at least, two cases in that Boot Camp fails to install: (1) If Windows is booted without OpenCore and (2) if Boot Camp's installer folder was renamed.

(12) Credits: All credits goes to OpenCore developers, big thanks to all!
Reply With Quote

boot, dual, macos, opencore, ssd, windows
Thread Tools

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.