I used Calyx with an esim. I switch over to Graphene to try it and decided to keep Calyx as my OS. When I chose to set up an esim, it was automatically installed.
How is this possible? I flashed two different OS, how did they manage to sent me, my esim?
I cant answer your question directly but I’d like to share some relevant stuff I learned about phones.
Cell phones have a modem (the bit that provides wireless connectivity).
The modem contains radios for communication, and its own CPU. The firmware on that CPU is, in almost all cases, a closely guarded company secret.
The modem starts before the rest of your phone, it can communicate with the carrier towers and can do whatever it wants before your main CPU wakes up. Accessing RAM, initialising the main CPU etc, this is why some people feel hardware kill switches should be a common thing.
That sounds interesting, could you provide some sources?
