Are you serious? Absolutely not. Unless you can show that you are competent to modify safety critical software, and have a certified process in place to do that, it would be illegal for you to modify the code, and you would be personally liable for any accidents caused by such a modification.
You would also require the full lifecycle documentation to allow you to understand the impact of any modifications you make, and be required to do a full impact analysis to prove that any modifications you make do not reduce the integrity of the existing safety functions.
That's completely ignoring the vendor's configuration management requirements (which you can't do).
This the whole point - devices run by software systems are too complex to be modified by a layman. There are very detailed, statutory processes and requirements around the development and modification of software in safety critical applications, and you absolutely cannot modify it just because you bought it.
You would also require the full lifecycle documentation to allow you to understand the impact of any modifications you make, and be required to do a full impact analysis to prove that any modifications you make do not reduce the integrity of the existing safety functions.
That's completely ignoring the vendor's configuration management requirements (which you can't do).
This the whole point - devices run by software systems are too complex to be modified by a layman. There are very detailed, statutory processes and requirements around the development and modification of software in safety critical applications, and you absolutely cannot modify it just because you bought it.