Package: debian-installer Version: 20210415 I just tried using the hd-media build to boot from an existing hard disk and install without using removable media and was not able to do so because I used btrfs on the hard disk, and most filesystems are packaged as separate udebs rather than being built into the initrd. I think it was only iso9660, fat, and ext4 that were in there. Please consider moving btrfs and probably a few other filesystem modules into the hd-media initrd so that it can be used outside of ext4 and fat.