A couple of days ago I decided to (re)install Windows 10 on my box, which was running only Debian, but I couldn't get the UEFI to boot the installer from the various USB, or even a DVD, I prepared. Nevertheless, Legacy mode was able to do so and hence I decided to install Debian, Windows 10 and FreeBSD in BIOS mode.
Is there a way to get back to UEFI keeping GRUB2 and the three OSs bootable, without reinstalling them?
Another question I'd like to be answered is: booting in Legacy mode has any impact on the performance of any of the OSs?
Thank you very much for your answers.