Hacking a firmware is for playkids only. If you want to have a reliable tool over a longer period then don't do this. The next time you update the regular firmware either your hacks are all gone or they don't work properly anymore.
Programaticability of a cameras is sort of uncommon, sadly. While I see some challenges, I do believe that it is possible to offer the feature while keeping the camera safe from "bricking"[1]. The problem is that the manufacturers are:
1. paranoid about their software a whether they perceive this a threat to their secrets
2. they seems to be unable to write proper software for PC[2]. And I'm talking about experience where both the Canon and Olympus software are horrible on Mac. Worse: they seem to not support the software for very long either leading to obsolete software that require obsolete OS to run. Exhibit: the Nikon CoolScan software.
3. they seem to not be open in general, which mean that this programmaticability feature would be tied heavily to them providing the PC software (see 2.) Exhibit: Canon, Olympus, Nikon that all refuse to document their tethering protocol and provide a SDK (for PCs) of dubious quality and support[3].
All in all this would lead to an obsoleting feature.
FWIW, their use to be a company back in the 90's and early 2000 that made a firmware for cameras know as Digita that allow programing the camera. Kodak had the DC220, 260, 265 and 290. But Google lead me to believe that the company is long gone.
Sorry, I had my software engineer hat today.
Cheers,
Notes:
[1] "bricking" is the action of rendering a device unusable by overwriting its firmware with something that does not work. This mostly happen when there is an error in the process
[2] PC means personal computer, whichever it is a Mac or runs Windows or Linux.
[3] There are actually solutions based on reverse engineering.