Yaird generates highly optimized initial ramdisks. These ramdisks cannot boot into a different system setup! Yaird is good for stable systems, like servers (especially if managed remotely) and embedded systems. Automatic firmware loading is not supported. You may need to either extend config files with custom shell snippets to load your firmware, or avoid SCSI drivers and similar that needs firmware to work. If you need a flexible ramdisk tool, then use initramfs-tools instead. If you need to do changes to your system setup that affect the path to the root filesystem (different disk driver, changes to RAID or LVM etc.) then temporarily enter the new root filesystem through some some other means (using a flexible ramdisk generator or with Debian-installer in rescue mode) to regenerate the ramdisk.