Sorry I didnt notice your entry before going on vacation.
The firmware passes the MAC address to the kernel in the device tree but I believe you can still add the property to the device tree at the time of creating your image.
So if you follow the db410 instructions on how to build the boot image, add the following change to your kernel tree (adjusting your MAC address), generate the new image and flash it with fastboot
[jramirez@igloo kernel.git (debian-qcom-dragonboard410c-16.09-local *$)]$ git diff
diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 551c12a..7cf949e 100644
@@ -1129,6 +1129,7 @@
interrupts = <0 145 0>, <0 146 0>;
interrupt-names = "tx", "rx";
+ local-mac-address = [02 00 27 60 25 28];
qcom,state = <&apps_smsm 10>, <&apps_smsm 9>;
qcom,state-names = "tx-enable", "tx-rings-empty";
fastboot flash boot boot-db410c.img
Does this help?