dt overlays raspberry pi

Hi U-boot hackers,

we like to use u-boot as intermediate bootloader to create a raspberry pi based system with fallback partitions. This worked fine in the first tests.

Recently the raspberry pi project switched to Linux Kernel 3.18.x and a device tree enabled kernel.
I added fdtfile and stuff to load the dtb (bcm2708-rpi-b.dtb) into my u-boot environment and this works fine.

But we are using a rpi-proto audio chip (something like a hifiberry i2s connected daughterboard) which is enbaled in the Broadcom Bootloader via a Device Tree Overlay.

Is there any support for device tree overlays in u-boot for raspberry pi?

https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README

Is anyone working on this?

Thanks in advance
Waldemar