There is more open source code from the miner manufacturers than from any 3rd party firmware.
Doesn't do any good if you need a key to sign the image for it to be loaded into the miner...
Original firmware loads fine.
You may have problems loading 3rd party firmware that is all closed source, hides what it does internally, usually breaks the cgminer license and thus none of it falls under what you said:
...
Generally I would be happy with a higher level of openness/interoperability/transparency in the mining HW business.