macOS installer

To download a full installer

For macOS Big Sur

softwareupdate --fetch-full-installer --full-installer-version 11.3

Replacing the version will download the version - e.g. Catalina has version 10.15.3

Converting installer to iso

hdiutil create -o /tmp/BigSur -size 12500m -volname BigSur -layout SPUD -fs HFS+J

hdiutil attach /tmp/BigSur.dmg -noverify -mountpoint /Volumes/BigSur

sudo /Applications/Install\ macOS\ Big\ Sur/Contents/Resources/createinstallmedia --volume /Volumes/BigSur --nointeraction

hdiutil detach /Volumes/BigSur/

hdiutil convert /tmp/BigSur.dmg -format UDTO -o ~/Desktop/BigSur.cdr

mv ~/Desktop/BigSur.cdr.dmg ~/Desktop/BigSur.iso

Create Virtualbox VM

VBoxInternal/Devices/efi/0/Config/DmiSystemProduct" "MacBookPro11,3"

VBoxManage setextradata "Big Sur" "VBoxInternal/Devices/efi/0/Config/DmiSystemVersion" "1.0"

VBoxManage setextradata "Big Sur" "VBoxInternal/Devices/efi/0/Config/DmiBoardProduct" "Mac-2BD1B31983FE1663"

VBoxManage setextradata "Big Sur" "VBoxInternal/Devices/smc/0/Config/DeviceKey" "ourhardworkbythesewordsguardedpleasedontsteal(c)AppleComputerInc"

VBoxManage setextradata "Big Sur" "VBoxInternal/Devices/smc/0/Config/GetKeyFromRealSMC" 1

VM screen size

It seems macOS on VBox is limited to 1024x768, 1280x720, 1920x1080, 2560x1440

VBoxManage setextradata "Big Sur" "VBoxInternal2/EfiGraphicsResolution 1280x720"