This worked on Raspbian as follows:
- Make a machine-specific boot folder
tftpboot\<Serial#>on the server
cmdline.txtroot as the SSD's PARTUUID
/bootto mount from
However, when I tried the same with Ubuntu 20.04 arm64 server it fails to boot.
I can get Ubuntu 20.04 to start with a SD card as boot media, which outputs this on boot:
Net: No ethernet found. starting USB... No working controllers found ## Info: input data size = 6 = 0x6 Hit any key to stop autoboot: 0 switch to partitions #0, OK mmc0 is current device Scanning mmc 0:1... Found U-Boot script /boot.scr …
But when I attempt it via network boot, instead of "switch to partitions #0, OK" I get:
Card did not respond to voltage select! Card did not respond to voltage select! starting USB... No working controllers found USB is stopped. Please issue 'usb start' first. starting USB... No working controllers found No ethernet found. missing environment variable: pxeuuid … U-Boot>
And although this ends with a U-Boot prompt, USB isn't working at this stage so I can't do anything with it.
The NFS server shows that the client is fetching files during the network boot (otherwise, it would have nowhere to get U-Boot from).
Although the working 20.04 boot prompts "Hit any key to stop autoboot", keyboard doesn't work here either, so perhaps USB just doesn't work at this stage of this image's boot process.
Is there anything I can do to get more information on what's going wrong?