A more detailed guide for dropbear: cyberciti.biz/…/how-to-unlock-luks-using-dropbear…

If I remember correctly, the only outdated bit of information is that the IP configuration doesn’t happen anymore in the initramfs configuration but you must pass a parameter at the kernel by editing /etc/default/grub and passing

GRUB_CMDLINE_LINUX_DEFAULT=“ip=192.168.x.x:::::”

where 192.168.x.x is the IP address that you want at boot