cecoppola wrote:spend time downloading more software that may be totally unnecessary.
You of course can do what you want to do. But the wise, when they come to experienced advisers, don't poo-poo the advice.
Your first question:
cecoppola wrote:what is the best way to virtualize an existing, bootable Linux partition from within Windows 10?
The best way is bring the OS on the physical disk into a virtual disk, not to use raw disk access.
mpack wrote:raw VMDK is a stopgap only. It would be better to convert the disk to a dynamic VDI
Question answered.
Raw disk access is fraught with danger: On Windows hosts you must run the VM as Administrator, which opens further vectors for malware to infect the host. If the host one day decides to enumerate the physical drives differently, the raw disk vmdk will point at a different disk, resulting in data damage. Raw disk access is for experts only (even the manual says that), and we don't help folks do raw disk access.
You later changed your question to force using raw disk:
cecoppola wrote:The system I want to virtualize has its own disk. ... This OS will keep its own physical disk and I can modify it from inside by booting into it. Given that, what is the best way to virtualize it inside of WIndows 10?
This restriction requires raw disk access. Per the above, we don't help folks do raw disk access. A mistake made will destroy the host OS or the disk's data.
The method described in the manual using the vmdk descriptor file
https://www.virtualbox.org/manual/ch09.html#rawdisk is the only way to do raw disk access in Virtualbox.
If you are willing to forget about raw disk access and virtualize the drive's OS to a complete virtual disk file on the host (and you may be able to add another disk to the host to hold the virtual disk file so the host does not lose disk space), the easiest method to do that is with CloneVDI, read the instructions with that program.
The boot failure or EFI shell issues may happen no matter what method for running the disk's OS you use. Once any computer, physical or virtual, turns on, it looks for an OS and tries to run it. If the disk's boot loader is an unexpected configuration, errors may happen.
If the original computer for that drive was UEFI, the VM should use EFI. If the original computer for that drive was legacy BIOS, the VM should use BIOS. Further glitches after using the correct boot environment will have to be fixed by web-searching the error and fixing the boot loader directly.