Problem with more than 1 interface

[LordBadHabit]

Hi everyone,

I´m in the process of developing a small PXE solution for our industrial machines and I´m using iPXE to load what I need there.

Now, some of these machines have more than 1 NIC, maybe 2-4 ,usually at least 2 of them are connected and sometimes this leads to the following issue:

Machine starts up, PXE ROM receives an IP and loads menu, then starting an option like this:
LABEL 5
MENU LABEL MyBootOption
KERNEL /Linux/iPXE/ipxe.lkrn
APPEND dhcp && chain http://1.2.3.4/whattodonext.php

Now I´ve seen 2 different things happen on the same device, within 5 minutes and 10 reboots:

Possibility 1: NIC comes up, receives IP, further commands are loaded via the PHP file, everything nice

Possibility 2: Trying to "up" eth0 and failing. The MAC showed is NOT the correct one, therefore I guess ipxe is trying one of the other internal interfaces and fails (depending on machine type they may be up or disconnected).
It is not trying to bring up other interfaces but fails immediately....

Unfortunately I can´t reproduce this error on test machines and my "playtime" with the real device is very limited due to business reasons. So I was hoping that one of you could tell me what to add to the "dhcp" line in the IPXE script that would ensure trying on all interfaces first before proceeding.

Would something like
APPEND :retry && dhcp || goto retry && chain http://1.2.3.4/whattodonext.php

work or would it just be searching for DHCP on the wrong interface forever?

Any help is very much appreciated!

Thanks in advance
LordBadHabit