pi3 network boot broken

[cleverca22]

Describe the bug
tftp client in start.elf is broken

To reproduce
attempt to network boot a pi3 with the latest firmware, using https://github.com/openSUSE/xinetd and https://github.com/mmaraya/netkit-ftp/tree/master

Expected behaviour
the rpi to actually boot

Actual behaviour
all tftp transfers finish and then act like the file didnt exist

• Which model of Raspberry Pi? Pi3B+

Logs
If applicable, add the relevant output from dmesg or similar.

[clever@amd-nixos:~/apps/rpi/firmware/boot]$ git bisect bad
11a76e07ef1b6304a378c4ee3da200fe6facea46 is the first bad commit
commit 11a76e07ef1b6304a378c4ee3da200fe6facea46
Author: popcornmix <[email protected]>
Date:   Thu Apr 16 12:40:43 2020 +0100

    firmware: Switch to building from common firmware branch

Additional context

[root@router:/tftproot/arch64_be]# cat xinetd.conf
service tftp
{ 
  protocol    = udp


  socket_type = dgram

  wait        = yes
  user        = nobody
  server      = /nix/store/bpkwjqrfbg32cky75fz219p4367gy16j-netkit-tftp-0.17/sbin/in.tftpd
  server_args = /tftproot

}
[root@router:/tftproot/arch64_be]# ps aux | grep xinet
root        3721  0.0  0.0   6064  2944 pts/1    S+   Aug03   0:00 xinetd/xinetd -syslog daemon -dontfork -stayalive -f /nix/store/8188a7il2r5yw1bfm3ji3896cb8akm0l-xinetd.conf

MESS:00:00:11.811188:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:11.815249:0: gpioman: gpioman_get_pin_num: pin LEDS_PWR_OK not defined
MESS:00:00:11.834101:0: brfs: File read: -2 bytes
...
MESS:00:00:12.233990:0: dtb_file 'bcm2710-rpi-3-b.dtb'
MESS:00:00:13.260260:0: brfs: File read: /mfs/sd/bcm2710-rpi-3-b.dtb
MESS:00:00:13.264916:0: Loading 'bcm2710-rpi-3-b.dtb' to 0x100 size 0x0
MESS:00:00:13.317771:0: brfs: File read: -2 bytes
MESS:00:00:13.324590:0: dterror: out of memory
MESS:00:00:14.516181:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:14.538462:0: brfs: File read: -2 bytes
MESS:00:00:18.777509:0: brfs: File read: /mfs/sd/cmdline.txt
MESS:00:00:18.781461:0: Failed to read command line file 'cmdline.txt
MESS:00:00:21.112313:0: gpioman: gpioman_get_pin_num: pin EMMC_ENABLE not defined
MESS:00:00:21.296502:0: brfs: File read: -2 bytes
MESS:00:00:21.338002:0: No compatible kernel found

when booting, every tftp request ends with the rpi sending "Early terminate" and the uart logs then claiming -2 bytes read
it then ignores the kernel specified in config.txt, and tries loading the default path, and fails

unfortunately, a bisect of the firmware repo points to the commit where the pi4 code got merged in, and it has remained broke until latest master

[timg236]

Pi3B and Pi3B+ seem to be working ok with network boot here with Bookworm 64-bit

Did you upgrade bootcode.bin as well as start.elf

root@pxe:/tftpboot/44bee3d2# sha256sum bootcode.bin
6505bbc8798698bd8f1dff30789b22289ebb865ccba7833b87705264525cbe46 bootcode.bin

start.elf
VC_BUILD_ID_USER: dom
VC_BUILD_ID_TIME: 15:31:28
VC_BUILD_ID_VARIANT: start
VC_BUILD_ID_TIME: May 24 2024
VC_BUILD_ID_BRANCH: bcm2711_2
VC_BUILD_ID_HOSTNAME: buildbot
VC_BUILD_ID_PLATFORM: raspberrypi_linux
VC_BUILD_ID_VERSION: 4942b7633c0ff1af1ee95a51a33b56a9dae47529 (clean)