Android has it as a toggle: https://source.android.com/docs/security/features/cellular-s...
iPhone disables it for phones in lockdown mode.
I wonder if this mostly hit international SIMs, since they wouldn’t be running the same level of SIM code to prefer various network locks like a local SIM.
Helps you stay under the radar and gov services over SMS is a lot more advanced outside of Canada if you want to do some fraud.
Source? It might just be that your carrier retired its 2g/3g network, not that the phone/sim refuses 2g/3g connections. If some cell tower popped up claiming to 2g/3g, your phone still might happily connect.
my Telus/Bell SIM shows the 3G network tho
Absent that, maybe this happens via a carrier profile (or equivalent mechanism)?
But I only have an option for data roaming on/off, not roaming entirely.
It sounds like a good idea to at least restrict 2G connections to non-roaming scenarios, but then you have the next practical problem: How does your baseband know that you're abroad?
Sure, all solvable at the application layer (the phone could use location heuristics to figure out where it is etc.), but not trivial and full of edge cases that could easily result in your phone mysteriously not connecting while abroad or, worse, not being able to make an emergency call or similar.
Although now looking at Wikipedia there are a lot more 2G networks sticking around than I realised, still hard for me to believe given what's happened here!