Nothing would boot for me until I set EFI/SMC vars

[cweagans]

From https://www.maketecheasier.com/install-macos-virtualbox/:

VBoxManage setextradata "[name of vm]" "VBoxInternal/Devices/efi/0/Config/DmiSystemProduct" "iMac11,3"
VBoxManage setextradata "[name of vm]" "VBoxInternal/Devices/efi/0/Config/DmiSystemVersion" "1.0"
VBoxManage setextradata "[name of vm]" "VBoxInternal/Devices/efi/0/Config/DmiBoardProduct" "Iloveapple"
VBoxManage setextradata "[name of vm]" "VBoxInternal/Devices/smc/0/Config/DeviceKey" "ourhardworkbythesewordsguardedpleasedontsteal(c)AppleComputerInc"
VBoxManage setextradata "[name of vm]" "VBoxInternal/Devices/smc/0/Config/GetKeyFromRealSMC" 1

Neither Mojave nor High Sierra would boot until I set those values.

[sify21]

Saved my day!