Emergency calls bypass the network restriction. I don't see it documented for Gr... | Hacker News

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		flotzam on April 28, 2025 \| parent \| context \| favorite \| on: Did 5G kill the IMSI catcher? Emergency calls bypass the network restriction. I don't see it documented for GrapheneOS, but https://source.android.com/docs/security/features/cellular-s... states 'Android allows users to disable 2G at the radio hardware level on any device that implements the capability constant, "CAPABILITY_USES_ALLOWED_NETWORK_TYPES_BITMASK". This stops a device from scanning or connecting to 2G networks. Note: Emergency calling is never impacted. A device still scans and connects to 2G networks for emergency services.'

vv_ on April 28, 2025 [–]

I guess it makes sense as Emergency Calls are highly regulated.

It still applies for normal calls though. I guess this is why major smartphone operating systems do not allow you prevent 2G/3G registration.

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