Neither. The solution is simple: don't fix non-vulnerabilities for the purpose of breaking jailbreaks/unlocks. In a number of cases, jailbreaks have been done

Neither. The solution is simple: don't fix non-vulnerabilities for the purpose of breaking jailbreaks/unlocks. In a number of cases, jailbreaks have been done via real vulnerabilities, e.g. browser vulns, but this is 1) due to closing "security holes" that enabled early jailbreaks, and 2) not the majority.