No doctor will want to be associated with installation of a life-support device which the patient can reprogram at will. Every change, starting from creation of the first blank main.c file, MUST be documented as considered, deliberated, implemented, reviewed, tested, verified, validated, and documented by certified personnel to the satisfaction of everyone from patient to surgeon to maintenance doctor to board of directors to sovereign jurisdictional government. We're not talking "oops, reboot" or "get the backup" or "revert to the previous version" failures should a mistake be made, we're talking "patient will die in 30 seconds flat if you screw up".

Writing a FOSS version of the software keeping me alive right now sounds lofty, but I don't think the surgeon who installed my pacer would have done so if he thought I might actually replace the software outright, and the doc & techs who maintain it certainly wouldn't continue to.

The potential positive benefits of an open-sourced pacemaker are obvious and well-expressed. Oft missed are the litigative & metabolic nightmare scenarios. One dangling pointer and I'm dead.