bmd
Island in the stream.
In most scenarios you shouldnt bother entertaining such thoughts. For numerous reasons including lack of sourcecode for the original firmware, lack of documentation, possible lack of hardware tools necessary for development. And the complexities of this sort of low-level programming. There are exceptions, but they are few and far between and tend to require a specific subset of reasonably advanced programming skills. Especially when it comes to corporate products as opposed to more homebrew type devices that might have been built on a more open DIY ecosystem in the first place. eg Linnstrument sourcecode is available, so I could modify that if I had the desire and time.
Are you saying that you don't recommend it?