maybe try resetting your nvram at the boot picker
when turning on laptop, hold down the alt button until you see the picker menu
Successful move to Big Sur.
Starting point:
Dual Boot Windows 10 and Catalina with Cover on Asus Laptop N752.
Actions before update:
-Full back up with CarbonCopyCloner and Time Machine
-Using Dortania guide on Windows to move to OpenCore. Created USB installer with Catalina and reinstalled it and recovered with Time Machine Backup. Only basic Kexts and Patches used
-Finished OpenCore setup on Catalina, added all patches and necessary Kexts. Everything working, FN Keys, Wireless, Bluetooth, screen resolution...
-Amended OpenCore to have a GUI showing Windows and Mac OS system
-Again full backup with Carbon Copy Cloner and Time Machine
Update:
-downloaded Big Sur in System Updates and followed the steps
-System reboots a couple times, complete update required just under one hour. No issues, no freezes
Things working:
-All applications including FaceTime, Messages and Music
-Fn Keys, Screen Brightness, Volume, Airplane, etc
-Wireless, Bluetooth, Bluetooth mouse, trackpad
-Battery status
-Siri
-Dual Boot with Windows 10
-Icloud and Photos synchronisation
Things not working:
-So far only Netflix and Apple TV not working. Maybe related to DRM issues. Didn't look into it yet.
[Edit]: Netflix works when using Chrome browser.
Thanks and can
@Feartech for all the guidance and support. Couldn't have done it without you...