mount_hammer2 is probably not in initrd
FreeBSD on the laptop has decent support, and in a couple of weeks you will learn about initrd etc. to be able to work with DragonflyBSD.
If you want to learn more about system internals, you might want to learn how to use bhyve (FreeBSD's awesome hypervisor) on FreeBSD. By trying to use bhyve you will learn how to extract the kernel from an img build, load it etc.
Have fun and good luck on your studies!