On a laptop where I already have elementary OS 5 installed in BIOS mode (no /boot/efi partition), I am trying to install elementary OS 6 from USB, and I would like to keep the system booting in BIOS, not UEFI, mode. However, the installer always insists on a separate /boot/efi partition in the partitioning step. (This is not the case on another laptop where I tried installing, where just a / partition was sufficient.) I checked the BIOS boot settings, and it's set to Legacy Support (Legacy First). I tried searching for an installer boot option to force BIOS mode but did not come to something. Any pointers are appreciated.