Hi
I have a UEFI Linux instalation that is started by GRUB.
I can ESC in GRUB then enter exit to start rEFInd that loads BIOS Windows, but only if CSM is on in the UEFI and the boot entries are set properly, meaning that at least one points to the MBR of Windows.
I hope this helps people to start MBR Windows installations with their UEFI Linux installations without having to make a passthrough VM.
