How to install macOS Big Sur on an Unsupported Mac

My Test: MacBook Pro Late 2011

1. By "Disk Utility" => add "New Volume" to "Your SSD" as "APFS format"

2. By "Disk Utility" => format USB : from top device (Erase : Mac OS Extended (Journaled)) : after select "Show All Devices" : then "Erase" from Top of "USB"

   • Name: MyVolume
   • Format: Mac OS Extended (Journaled)
   • Schme: GUID Partition Map
   • if you use "SD Card", do not use "USB hub", use "usb sd card reader"

3. Download : InstallAssistant.pkg http://swcdn.apple.com/content/downloads/50/49/001-79699-A_93OMDU5KFG/dkjnjkq9eax1n2wpf8rik5agns2z43ikqu/InstallAssistant.pkg https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/

4. Run "InstallAssistant.pkg" for install app "Install macOS Big Sur" -- or from "App Store" search for "macOS big sure" -> get

5. From "Terminal" run command : after go to : Application -> "Install macOS Big Sur" -> "Show Package Contents" : sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

6. Download code from "https://github.com/barrykn/big-sur-micropatcher"

7. From "Terminal" run command "micropatcher.sh" to "USB" ("Install macOS Big Sur") : .../micropatcher.sh /Volumes/Install\ macOS\ Big\ Sur

8. From "Terminal" run command "install-setvars.sh" to "USB" ("Install macOS Big Sur") : .../install-setvars.sh /Volumes/Install\ macOS\ Big\ Sur

9. Restart your Mac and press "alt" key until see the "apple" logo, then select your USB ("Install macOS Big Sur")

   • after go to "Recovery" go to "Terminal" from "Utility menu" then :
   • run command "csrutil disable" ***************
   • run command "csrutil authenticated-root disable"
   • select "Install macOS" for "Install macOS Big Sur" and select "Your SSD"

10. After install "macOS Big Sure" :

    • Plug in USB "Install macOS Big Sur" then restart Your Mac and press "ALT" key then select your "macOS Big sure" disk
    • From "Terminal" run command : for fix wifi /Volumes/Install\ macOS\ Big\ Sur/patch-kexts.sh --2011
    • Restart Your Mac and press "ALT" key then select your "macOS Big sure" disk

11. Modifying the System volume yourself :

    • From "Terminal" run command : /Volumes/Install\ macOS\ Big\ Sur/remount-sysvol.sh

Sources :

Source 1 Source 2 Source 3 Source 4