@jaski.tx , Sorry for not mentioning this but we are compiling the kernel outside of OE. They are using current toradex_4.9-2.3.x-imx. The kernel binary and the DTB is then later substituted/added to the TEZI image we are using, nothing too crazy.
What we are mostly using poky-tiny (rocko, since it is 2.8) just to create the RFS with a lot of removed stuff.
This was basically a personal decision of starting from the very bottom (poky-tiny) rather than start removing stuff from our Angstrom. Almost everything works except a couple of extra stuff that we are currently solving with the customer.
Have you tried disabling the fec2 node without disabling the kernel driver? Do you see the same behaviour that Jaski’s?
Did you also tried doing so disabling the kernel driver and still get the kernel panic? Can I recommend you removing settings in the menuconfig one by one to try to find the culprit of the kernel panic?
Please also share the complete dmesg with us with the kernel panic (not sure if you already did)