Ian, your guide for PXE booting PI3B+ is a God Send, thank you so much for a brilliant guide. I have a few Pi's around the house, monitoring my Aquarium, controlling my home brew cider and wine, and doing some ambient lighting. My goal was to boot these all over PXE as SD worried me. The server is hosting all the file systems to the clients from an SSD drive, formatted to F2FS root (to load level it). With your help I've got the PI's booting perfectly, all through my 20.04 Ubuntu Server. I can now close the server down once a month and DD image the SSD to an archive HDD in case of a huge failure and restore the whole house! Thanks man, don't get coffee, go get a beer on me :)