In this YouTube video around 2:30 it is stated

There was no way to stop another company from making a game for your system.


Unlike now where you have to obtain a license to make a game legally for a video game system, you didn't need to back then...people just reverse engineered the systems.

How does this work? For example does Rockstar Games now need to obtain a license from Microsoft before making Grand Theft Auto for the Xbox? I didn't think someone could sell something but restrict what can be compatible with it? Obviously with a computer anyone is free to make any app they wish.

1 Answer 1


In the "old days", consoles were pretty simple affairs compared to what we have today - largely manufacturers relied on the cost of the physical cartridges to ensure lock-in and control over the available games on their systems, along with copyright control over the documentation required to properly code against the system.

Of course, it was possible to spend some time with a hardware debugger and discover exactly what the system was doing, and you could design your own compatible cartridge to use the console - so long as you did not include any copyrighted material in your cartridge hardware or software you were fine and you didn't have to pay any licensing costs to the manufacturer.

Times have changed however, both in terms of how complex consoles are and in terms of the legal situation surrounding them.

Modern consoles go a few steps further - they include cryptographically locked boot loaders and firmware, which allow the console manufacturer to require content to be digitally signed with specific keys, keys only the manufacturer has, before the console will load the content.

There are ways around this, you can remove the protection in the hardware by replacing it, or you can circumvent the firmware with new firmware which doesn't require a signature check, or you can in some cases include a signed file in your game which is checked.

The problem with these approaches is that invariably they require you to distribute code or a derivative of code which is copyrighted by the console manufacturer (because the firmware is more complex than just the signed bootloader and you really don't feel like writing something as complex from scratch, or because the files you need to include are copyrighted and signed by the console manufacturer and thus have to be perfect copies to match) - and this is where the main legal claim comes in.

Not only does the manufacturer have a copyright claim against you, but they can also bring the Digital Millennium Copyright Acts clause regarding circumvention of access control measures - which you would be doing in this case.

That is why its difficult to produce unlicensed games on modern consoles. Theoretically it can be done - you can replace the firmware with your own completely written from scratch or find another way to distribute your content which doesn't involve infringing on the console manufacturers copyright, but the manufacturers make this extremely difficult.

  • So now days a game has to be digitally signed to run on a console and the signature is only granted from the owner of the console? Hypothetically wouldn't it be easy just to copy the signature from another game? Nov 24, 2020 at 2:57
  • 2
    @raceinorbit321 signatures dont work like that, because its a signature of what the console is about to run - you cant change the code without changing the signature, so you cant just borrow a signature from another game.
    – user28517
    Nov 24, 2020 at 3:04
  • @raceinorbit321 Imagine the owners of the platform take the entire game code, encrypt it with a secret key, and then take some subset of the result, and include that with the game. Then if someone wants to know whether the owner authorized the game, they just have to check whether the subset of the encrypted version is what it should be. No one else can create the right subset without knowing the secret key, and the subset for each game is different, so you can't copy it from another game. Nov 25, 2020 at 0:06
  • And it's possible to check the subset without knowing the secret key (each secret key is paired with a public key, and the public key allows people to check a subset, but not create one). That's a very simplified version of what it means to digitally sign something. Nov 25, 2020 at 0:06

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