bootcode.bin randomly doesn't PXE boot correctly.

[ali1234]

I am using the latest version of bootcode.bin: https://github.com/raspberrypi/firmware/blob/f85646a8831d9579c2a745478149598da1ecfde5/boot/bootcode.bin

It is the only file on my SD card. I am using a Raspberry Pi 3.

Sometimes (but rarely) PXE boot works and sometimes it does not. I have to power cycle the Pi several times to make it boot.

Looking at the failed tcpdump log you can see that dnsmasq is replying to the boot request, but the Pi ignores it and sends another, for a total of 5 requests. Then it tries to request tftp files from 0.0.0.0.

dnsmasq log of failed session:

dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...

tcpdump port tftp or port bootpc from failed session:

07:46:27.892426 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
07:46:27.892915 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..V....@............C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
07:46:32.893294 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
07:46:32.893647 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..V....@..v.........C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
07:46:38.640376 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
07:46:38.640795 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..V.
..@.. .........C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
07:46:44.639980 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
07:46:44.640339 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..V.a..@............C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
07:46:50.639971 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
07:46:50.640411 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..V.b..@............C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
07:46:56.657068 IP 0.0.0.0.49153 > 0.0.0.0.tftp:  29 RRQ "autoboot.txt" octet tsize 0
E..9......:............E.%....autoboot.txt.octet.tsize.0.
07:46:57.657080 IP 0.0.0.0.49154 > 0.0.0.0.tftp:  27 RRQ "config.txt" octet tsize 0
E..7......:............E.#....config.txt.octet.tsize.0.
07:46:58.657351 IP 0.0.0.0.49155 > 0.0.0.0.tftp:  29 RRQ "recovery.elf" octet tsize 0
E..9......:............E.%....recovery.elf.octet.tsize.0.
07:46:59.657412 IP 0.0.0.0.49156 > 0.0.0.0.tftp:  26 RRQ "start.elf" octet tsize 0
E..6......:............E."....start.elf.octet.tsize.0.
07:47:00.773516 IP 0.0.0.0.49157 > 0.0.0.0.tftp:  26 RRQ "fixup.dat" octet tsize 0
E..6......:............E."....fixup.dat.octet.tsize.0.

[ghollingworth]

You're using a proxy server for the DHCP proxy and TFTP boot, do you also have a standard DHCP server as well replying with an IP address?

From the output it looks like you've got everything set up correctly (option 43 looks fine), it will only continue if it finds both an option 43 which tells it that the dhcp server is also going to serve the files and it has an IP address. From the information above no IP address has been offered.

Gordon

[ali1234]

My ADSL router is a DHCP server, yes.

[ghollingworth]

So can you dump that DHCP response as well?

[ali1234]

I ran "sudo tcpdump -A -i eth0 port tftp or port bootpc or port bootps or port 546 or port 547"

I did not capture any DHCP requests from the pxeserver to the main router. Output was the same as before.

[ghollingworth]

To debug this what I would do is to use the managed switch I have on my desk to mirror all traffic to a port with a Raspberry Pi on it... I'm wondering whether it's a STP problem with the switch in the router?

One thing we're going to do soon is to add the ability to provide serial debug from the bootcode, which should help with this...

Gordon

[ali1234]

I have a dump from the router itself now:

non working:

08:42:03.321057 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
08:42:08.321401 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
08:42:08.322173 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
08:42:11.069915 IP router.lan.bootps > xxx.xxx.xxx.113.bootpc: BOOTP/DHCP, Reply, length 343
08:42:14.070079 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
08:42:14.070707 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
08:42:14.071108 IP router.lan.bootps > xxx.xxx.xxx.113.bootpc: BOOTP/DHCP, Reply, length 343
08:42:20.069788 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
08:42:20.070493 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
08:42:20.070818 IP router.lan.bootps > xxx.xxx.xxx.113.bootpc: BOOTP/DHCP, Reply, length 343
08:42:25.069862 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
08:42:25.070624 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
08:42:25.070893 IP router.lan.bootps > xxx.xxx.xxx.113.bootpc: BOOTP/DHCP, Reply, length 343
08:42:31.086955 IP 0.0.0.0.49153 > 0.0.0.0.tftp:  29 RRQ "autoboot.txt" octet tsize 0
08:42:32.086983 IP 0.0.0.0.49154 > 0.0.0.0.tftp:  27 RRQ "config.txt" octet tsize 0
08:42:33.087249 IP 0.0.0.0.49155 > 0.0.0.0.tftp:  29 RRQ "recovery.elf" octet tsize 0
08:42:34.087316 IP 0.0.0.0.49156 > 0.0.0.0.tftp:  26 RRQ "start.elf" octet tsize 0
08:42:35.087460 IP 0.0.0.0.49157 > 0.0.0.0.tftp:  26 RRQ "fixup.dat" octet tsize 0

[ali1234]

Someone just turned on a Windows laptop on the network and now it started working correctly:

dnsmasq:

dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 available DHCP subnet: xxx.xxx.xxx.255/255.255.255.0
dnsmasq-dhcp: 653460281 vendor class: PXEClient:Arch:00000:UNDI:002001
dnsmasq-dhcp: 653460281 PXE(enp0s31f6) b8:27:eb:xx:xx:xx proxy
dnsmasq-dhcp: 653460281 tags: enp0s31f6
dnsmasq-dhcp: 653460281 broadcast response
dnsmasq-dhcp: 653460281 sent size:  1 option: 53 message-type  2
dnsmasq-dhcp: 653460281 sent size:  4 option: 54 server-identifier  xxx.xxx.xxx.5
dnsmasq-dhcp: 653460281 sent size:  9 option: 60 vendor-class  50:58:xx:xx:xx:xx:xx:xx:xx
dnsmasq-dhcp: 653460281 sent size: 17 option: 97 client-machine-id  00:f5:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-dhcp: 653460281 sent size: 32 option: 43 vendor-encap  06:01:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx...
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/autoboot.txt not found
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/config.txt to xxx.xxx.xxx.114
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery.elf not found
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/start.elf to xxx.xxx.xxx.114
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/fixup.dat to xxx.xxx.xxx.114
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery.elf not found
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/config.txt to xxx.xxx.xxx.114
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/dt-blob.bin not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery.elf not found
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/config.txt to xxx.xxx.xxx.114
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/bootcfg.txt not found
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/cmdline.txt to xxx.xxx.xxx.114
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery8.img not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery8-32.img not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery7.img not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/recovery.img not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/kernel8.img not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/kernel8-32.img not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/armstub8.bin not found
dnsmasq-tftp: error 0 Early terminate received from xxx.xxx.xxx.114
dnsmasq-tftp: failed sending /home/al/pi-tftp/tftpboot/kernel7.img to xxx.xxx.xxx.114
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/armstub8-32.bin not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/armstub7.bin not found
dnsmasq-tftp: file /home/al/pi-tftp/tftpboot/armstub.bin not found
dnsmasq-tftp: sent /home/al/pi-tftp/tftpboot/kernel7.img to xxx.xxx.xxx.114

router, tcpdump -i br0 port tftp or port bootpc or port bootps or port 546 or port 547:

09:00:40.285719 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
09:00:45.725710 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
09:00:45.726339 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
09:00:45.727086 IP router.lan.bootps > rootfs.lan.bootpc: BOOTP/DHCP, Reply, length 343

pxeserver, tcpdump -A -i enp0s31f6 port tftp or port bootpc or port bootps or port 546 or port 547:

09:00:38.856729 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
09:00:38.857410 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..VB...@.uG.........C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
09:00:44.297417 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b8:27:eb:xx:xx:xx (oui Unknown), length 322
E..^......9..........D.C.J......&..9.....................'..............................................................................................................................................................................................................c.Sc5..7.+<C........B..]...^....a..................< PXEClient:Arch:00000:UNDI:002001.
09:00:44.297964 IP pxeserver.lan.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 314
E..VD5..@.s..........C.D.B......&..9.....................'..............................................................................................................................................................................................................c.Sc5..6.....<	PXEClienta..................+ ...
..PXE	....Raspberry Pi Boot..
09:00:44.316425 IP rootfs.lan.49153 > pxeserver.lan.tftp:  29 RRQ "autoboot.txt" octet tsize 0
E..9...........r.......E.%....autoboot.txt.octet.tsize.0.

[ali1234]

Also I can run "brctl showstp br0" on my router. It shows a lot of information but I don't really know what I am looking for.

[ghollingworth]

It looks like a problem we had before where we needed a broadcast packet to trigger the receiving of one of the packets (which is why turning on the Windows machine suddenly starts it...)

Be interesting to see if the receipt of the second DHCP reply was triggered by a broadcast packet...

[ali1234]

That is probably it. The Windows machine is spamming a lot of autoconfig junk continuously on both IPv4 and IPv6. The Pi and the pxe server are both connected directly to the router switch, but the windows machine is behind a second (unmanaged) switch. None of the machines are on wifi, but the router is bridging ethernet and two wifi radios.

[ghollingworth]

I might have to see if it's possible the USB->ETH bridge is holding onto a packet for some reason, or that I've dropped a packet... But can't understand why this would be...

In the past we've found doing an occasional broadcast ping will fix the problem...

[ali1234]

I found it not working again this morning. Broadcast ping brought it to life:

ping -b 192.168.0.255

[puck]

I'm seeing this roughly one time in 3 when I network boot my RPi 3, tcpdump from the DHCP server:

00:09:54.601333 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from b8:27:eb:52:63:05, length 320
00:09:54.602403 IP 10.1.0.251.67 > 10.1.0.203.68: BOOTP/DHCP, Reply, length 366
00:09:55.861047 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from b8:27:eb:52:63:05, length 320
00:09:55.862176 IP 10.1.0.251.67 > 10.1.0.203.68: BOOTP/DHCP, Reply, length 366
00:09:56.894372 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from b8:27:eb:52:63:05, length 320
00:09:56.895385 IP 10.1.0.251.67 > 10.1.0.203.68: BOOTP/DHCP, Reply, length 366
00:09:57.915143 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from b8:27:eb:52:63:05, length 320
00:09:57.916157 IP 10.1.0.251.67 > 10.1.0.203.68: BOOTP/DHCP, Reply, length 366
00:09:59.606050 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from b8:27:eb:52:63:05, length 320
00:09:59.607080 IP 10.1.0.251.67 > 10.1.0.203.68: BOOTP/DHCP, Reply, length 366

I find it can take several power off reboots of the RPi before it works correctly. When it does, it only makes DHCP request once.

I don't have any network switches on my home network which have mirror ports.

[ghollingworth]

@puck Is your test with the bootcode.bin as a single file on the SD card?

[puck]

Hey @ghollingworth, no I'm networking booting and loading it from a TFTP server. I have no SD card in my RPi 3.