All the four freedoms need to be usable for something to be useful. If you can't upload a new copy, then being able to modify it is pointless I think.
I disagree. It might be possible for the software (or at least parts of it) to be used outside the original device.
Of course I would love the possibility to patch my toaster, but that might cause additional costs on the hardware side that would make the toaster not sell all too well.
I'm not sure if I interpret you correctly, but if your statement somewhat implies that having access to the software of a device is pointles if there is no possibility to upload modified versions, I *strongly* disagree. Being able to inspect how something works is *always* valuable, IMHO.
If you cannot excersise your freedoms due to a technical `restriction' (e.g. ROM soldered to the PCB), then what is the point of having partial freedom? You won't be able to excersie your rights to begin with...
But even if you do not have the source code in this case, you can still examine and inspect how it works.
Cheers