Earlier quoted context omitted.
>The best place to siphon data in 2019? Your phone. But can't you reverse engineer your phone and see what it's doing? And can't you monitor the network data it's sending? With a backdoor in long haul transport gear, academics, researchers, random hackers, watchdog groups, journalists, competitors, etc, don't have the ability to monitor for bad behavior.
AFAIK nobody has reverse-engineered even parts of the radio-firmware, the separate OS which has memory access to your other OS. Linux/Android/Iphones OS, is really just a guest, a side-show to what the radio-firmware can and is doing, ie spying.
I honestly believe that the theoretical DMA backdoor attack (and most other similar attacks) have been mitigated thoroughly. I am much more concerned about secretly held 0days (RCE) and most concerned about warrantless orders against cloud storage.
https://www.apple.com/business/site/docs/iOS_Security_Guide.... p41