I think my laptop supports only EFI/UEFI mode, however I don't have any bias against EFI, and I think pretty handy you can go in the setup from GRUB, rather than with a keys combination.
However eventually I discovered that you can't use EVIFARS on Virtualbox, the Debian installer can force UEFI MODE as fallback and this misdirected me, Arch works differently:
Warning:
- For BIOS systems and MBR disks, do not install a bootloader inside your virtual machine, this will not work since the MBR is not linked to the MBR of your real machine and your virtual disk is only mapped to a real partition without the MBR.
- For UEFI systems without CSM and GPT disks, the installation will not work at all since:
- the ESP partition is not mapped to your virtual disk and Arch Linux requires to have the Linux kernel on it to boot as an EFI application (see EFISTUB for details);
- and the efivars, if you are installing Arch Linux using the EFI mode brought by VirtualBox, are not the one of your real system: the bootmanager entries will hence not be registered.
- This is why, it is recommended to create your partitions in a native installation first, otherwize the partitions will not be taken into consideration in your MBR/GPT partition table.
This is out, without knowing better about Syslinux and Efistub I am going to use GRUB, now it is only left BTRFS...