[@Lmpkio][@Absolis]
Ultron's technopathy is not a supernatural ability, it's a manifestation of his automatic understanding and capability to assimilate any form of technology. He's basically an ultra-hacker, because his brain is a supercomputer and he has a more comprehensive knowledge and understanding of electronics than any human could ever possess. As such, due to the logical limitations of technology, it makes no sense for him to be able to hack into a closed system. A closed system isn't receiving any signals from outside, and the only way to hack something without making a direct connection is to use a signal. Even more advanced signals wouldn't work, because it's not receiving any signals.

Although there are some comics where Ultron's pulled some fairly awesome shit, he usually seems to be locked out of closed systems.