I'm a software/hardware hacker and I am wondering about how legal it is to replace the firmware of something. This something can be

  • a car

  • a chinese quadcopter

  • a phone

  • a Canon EOS 5D

  • a (connected) digital thermometer

  • a presence sensor

  • … anything.

I know that modify the firmware may be illegal (because of licensing/copying copyrights, usually).

But what if you can't even read the firmware, only replace it with one your wrote yourself?

1 Answer 1


It's yours - do what you like with it

Assuming that you are the legal owner of the device then you are entitled to do whatever you like with it: smash it with a sledgehammer, brush your teeth with it, upload firmware, etc.

Unless, what you would like to do is otherwise illegal ...


It is unlikely that in buying the item you also bought the copyright in the firmware. More likely you have a licence to use it and that permission is limited to what the licence allows.

So, if you can write the firmware without using their firmware as a starting point then you can upload your new firmware. Personally, I think it would be next to impossible to build working firmware without knowing what their firmware does but if you can do so: well done.


Some of the things you name require government regulated designs - cars and telephones spring to mind. Your firmware is not part of that government approval so, for example, you couldn't drive a modified car on a public road, or connect a modified telephone to a telecommunications carrier without getting those approvals.

  • Errh, is Australia really that harsh? We can drive modified cars over here, apart from basis structural requirements like the requirement for bumpers, hoods, brakes.
    – user6726
    Dec 12, 2016 at 1:40
  • @user6726 Modified vehicles (other than "cosmetic" modifications like, spoilers, sunroofs etc.) require an engineer's certificate to be registered for the first time (a "blue slip" - you also need a "pink slip" for a mechanic's check if the vehicle is over 3 years old and a "green slip" which is evidence of your 3rd party personal injury insurance - the colour names date from when they were actual pieces of paper of those colours, nowadays they are electronic and have no colour). Changing firmware would definitely require a blue slip.
    – Dale M
    Dec 12, 2016 at 1:44

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