Parsing “firmware” partition (to create kernel + rootfs) was implemented using OpenWrt downstream code enabled by CONFIG_MTD_SPLIT_FIRMWARE.
With recent upstream mtd changes we can do it in a more clean way for DTS targets. It just requires adding a proper “compatible” string to the “firmware” partition node.

I'd like all DTS supported devices to use that “compatible” and disable CONFIG_MTD_SPLIT_FIRMWARE eventually.

1) Default uimage
If you see:
2 uimage-fw partitions found on MTD device firmware
please use “denx,uimage”; e.g.

partition@70000 {
        label = "firmware";
        reg = <0x070000 0x790000>;
        compatible = "denx,uimage";
};

2) Netgear's uimage
If you see:
2 netgear-fw partitions found on MTD device firmware
please use “netgear,uimage”; e.g.

partition@70000 {
        label = "firmware";
        reg = <0x070000 0xf80000>;
        compatible = "netgear,uimage";
};

3) TP-LINK's firmware
If you see:
2 tplink-fw partitions found on MTD device firmware
please use “tplink,firmware”; e.g.

firmware@20000 {
        label = "firmware";
        reg = <0x020000 0xfd0000>;
        compatible = "tplink,firmware";
};

Please kindly:
1) Use that for all newly added devices
2) Port already supported devices you can test

--
Rafał