Yes, it is actually illegal to make a copy if you don't have the rights to make a copy, no distribution required. If you rent a DVD and make a copy of it, then return that DVD, you have distributed nothing but you still made an illegal copy. If you rent the DVD, make a copy, and then destroy the copy, you have still created an illegal copy, even if there's no evidence of it.
But that's completely irrelevant to the point. The argument that was originally given was "since manufacturers give updates to their BIOS for free download, I should therefore be allowed to download that BIOS and use it in an emulator" to which my response was "the manufacturer is giving owners of the hardware free downloads to updated BIOS. Downloading it from a third party source who does not have the rights to distribute it is illegal" which is basically what you were also saying, so I don't know what it is you were trying to argue here. Or were you simply agreeing with me? (except for the part about distribution being the illegal part, of course)
Actually, as soon as you returned one copy and kept one, you distributed a copy. So, yes, distribution was involved. In fact, technically, making the copy is not illegal until you return the original and keep the copy, so if you make a copy and destroy it before you return the original, then you never created an illegal copy. Making copies without distributing them is not illegal in the US.
(Edit: I should mention that in a way you are correct about the copy you make of the DVD being illegal, but it's because there is no legitimate purpose for making the copy. Basically, US copyright law starts out by saying that all copies of copyrighted material are illegal, and here are the exceptions (sort of like firewall rules that say that all connections are denied, and here are the exceptions). Then it goes on in the fair use part to say basically that anything that does not affect marketability (what they really mean is whether it's likely they could have sold at least one more original) of the material is allowed. So, since the only likely reason for you to make a copy of a DVD is to keep it for yourself when you return the original, it could be considered illegal. On the other hand, you could argue that ripping it to play on a tablet while you are renting it, and erasing the rip when you return it is a legitimate use.)
If you want to get into the technicalities, I believe that both renting and loaning without compensation are treated basically as temporary transfer of ownership. The concept of "first sale" is the basis for reselling, renting, and loaning copyrighted material. That is, if you buy a copy of something, then you can treat that copy just like any other physical property as long as you don't distribute additional copies, which means you can sell it, rent it out, or loan it out. The exceptions to this are that sound recordings (like CDs) and computer programs that can be installed cannot be rented or loaned
for commercial purposes. (This provision was added in 1990 because it was so easy to rent and copy sound recordings or install and return the media for computer programs. Now the same could be said of DVDs as CDs, really, but the law has never been extended to them).
Also, when you buy a copyrighted DVD, for example, you can create additional copies in other formats to use in other players, or things like that. If you later decide to sell that disc, it is perfectly legal to do so as long as you either include your additional copies in the sale, or destroy them.
Renting a DVD is treated the same way as a sale, which means transfer of copies must be complete, you cannot retain one copy and rent out another, and the person renting the DVD cannot return one copy and retain another. Technically, either party could make additional copies as long as they were transferred along with the original (although doing this makes little to no sense when dealing with rented media unless you are planning to violate copyright).
My original point was twofold. The first point is that downloading a BIOS from an authorized distributor and using it in an emulator is legal despite some publishers claims to the contrary. My second point was that, since legally owning one copy of a BIOS or ROM makes it legal for you to possess an additional copy, what difference should it make how you obtain the additional copy? Technically, getting the additional copy from a friend is illegal (unless he makes the copy from your original and returns both to you at the same time). Of course with online downloads the problem is that nothing is stopping people who have no original from obtaining a copy. However, why should downloaders who do have an original copy still be guilty of contributory infringement when they have a right to possess the copy? Technically, it may be illegal for you to download a copy of a BIOS that you already own from an unauthorized distributor, but for practical (ethical) purposes, it's not really much of a concern.
My actual reason for replying was that you said, "It is also within their power as copyright holder to define how that copy can be used, and they define it as updating official hardware," and that statement is not true. If you have a legally obtained copy of something and decide to incorporate it into a device to create a light show on your ceiling, or shred it up and sprinkle it on your breakfast cereal, it's none of the copyright holder's business, as long as you don't distribute additional copies.
(Edit: It should also be noted that wherever I talked about distribution, in some (though certainly not all) cases that would also include public display.)
