that depends on the firmware on on your interpretation of the requirements for source for that firmware.
I haven't seen anyone sued for the source of a firmware blob if the firmware blob itself didn't included GPL code in it. (as opposed to the firmware blob being used as data by GPL code and uploaded to a device)
A lot of the linux kernel developers consider the splitting of the firmware out of the source tree to be a waste of time from a technical and legal point of view, but they don't fight it because it shuts up the people who think that it does matter from a legal point of view.
besides, the GPL only comes in to play when you distribute the resulting binary. There's a huge amount of stuff that you can do (especially in a large company) without triggering this.