Why does the physical machine not boot from a GPT disk, from which it boots perfectly under VirtualBox?

Question

linux

Under VirtualBox, I installed Debian Stretch on a physical hard drive with GPT. The /boot partition on ext2 turned out with the boot, esp flags (is that correct?). The virtual machine is loaded from it without problems, but the physical machine is not. The BIOS simply does not consider this hard drive bootable (the same standard text: "Reboot And Select Proper Boot Device or Insert Boot Media in selectde Boot device"). Is it possible that on a 2014 motherboard, the BIOS does not know about the existence of GPT at all? Or do you need some other flags on the boot partition? Or why then does this configuration not cause problems for Virtualbox?
PS: I lived my life in the MBR era and somehow missed the onset of GPT and this EFI of yours (by the way, can it be related to the subject?).

Answer 1

Most likely the problem is just in the EFI. Look whether it is included in BOX'e and in BIOS'e.

Answer 2

If you are trying to boot into BIOS mode, you may not have your bootloader configured correctly. If you are using Grub then you need to configure your GPT partition in Hybrid GPT mode and create an additional BIOS boot partition (EF02). On a regular MBR partition, GRUB writes its initialization code to the free space between the MBR and the beginning of the first partition, starting from the second sector (EMNIP). In GPT, the second sector contains the service data of the GPT table itself, so Grub does not know by default where to enter its code. To do this, the trick is done with a small BIOS boot partition, where GRUB should write its code.
It's very likely that you didn't make such a partition and GRUB didn't install correctly.
Here is a little more information -https://wiki.gentoo.org/wiki/GRUB2#Partitioning_fo...