Very interesting indeed, and cast a new light on the trend to solder batteries in place. I was able to find this article about how this could work: https://pri

Very interesting indeed, and cast a new light on the trend to solder batteries in place. I was able to find this article about how this could work: https://privacyinternational.org/blog/1357/tech-companies-respond-reports-nsa-tracking-switched-mobile-phones https://privacyinternational.org/blog/1357/tech-companies-re... Apparently this relies on a software hijacking so that the phone is not really off. Another, actually better article: https://www.techdirt.com/articles/20130723/12395923907/even-powering-down-cell-phone-cant-keep-nsa-tracking-its-location.shtml https://www.techdirt.com/articles/20130723/12395923907/even-... also points to malware injection. This corroborates what I've heard here and there while working in the GSM industry: you could trust a phone that's turned off, if only you could trust it being actually turned off.