Closing this issue now since we are using initramfs-tools/live-initramfs.

As we are using live-initramfs this should be supported now. Though I can't 
test it myself because of lack of according hardware. I would highly appreciate 
any feedback on this issue!

I've to defer this issue as long as either:

* I've access to the appropriate hardware to integrate it within our /linux

or:

* we're using initramfs approach which provides udev out-of-the-box

Removing the release-stopper keyword as I don't have access to any systems 
which require firmware to be able to boot. It's a feature request but not a 
release-stopper for me.

JFTR: when using initramfs-tools providing udev this feature should be 
available OOTB, but as long as we have the /linuxrc-style initrd the feature 
can't be implemented that easy without having access to such a system requiring 
firmware loading.

Would be nice to have support for firmware loading inside initrd.

Supporting loading firmware(s) from external devices (like floppy and usb pen)
as well as loading already present firmware images would be great.

JFTRY: check out /lib/udev/firmware.agent