At least simple things like Intervalometer, would work with Canon Basic.
We have "factory" evprocs that ML calls for this reason. They work, unless they didn't and leave camera in weird state.
They have a bug in sw1/sw2 handling - callbacks are installed for that and if eg focusing fails, callback is not removed. It fires on next (even real) shot attempt, with null pointer (iirc on recursive lock) - crashing the camera.
If it even won't crash (if I reset CBRs myself after failed attempt), it leaves camera in a state where it thinks photo is developing but it is not.
If there's another possibility on EOS firmwares, I'll be happy to take it as like I mentioned on previous page I spent too much time on those functions that we used previously
