VoLTE stopped working after a software update

It worked yesterday. You updated. Now calls fail, or sound worse, or the VoLTE switch has disappeared from settings entirely.

This is a well-known failure and it has a specific cause, which is worth understanding because most of the advice about it is wrong.

What an update actually changes

Android does not decide on its own that VoLTE is allowed. It reads a carrier configuration — a set of per-network settings that says which features are permitted on which network, for which device models.

A system update can replace that configuration. Three things can go wrong when it does:

1. Your exact model is no longer listed as approved for VoLTE on your network, so Android stops offering the toggle.
2. The modem firmware changed, and the new build behaves differently on your carrier.
3. The stored IMS settings were reset, so the phone needs to re-register and has not.

Only the third has a reliable fix from your side. The first is a carrier decision.

Try these first, in this order

Cheapest and most likely to work first:

1. Toggle airplane mode for ten seconds. Forces a fresh network attach and IMS re-registration. This alone resolves the third cause above.
2. Restart the phone. Clears modem state that airplane mode does not.
3. Check the VoLTE toggle is still on. Updates reset it more often than they remove it. It may also have been renamed — look for HD Voice, 4G Calling, Enhanced 4G LTE Mode or Wi-Fi & mobile network calling.
4. Check for a carrier settings update. These ship separately from system updates and are frequently the actual fix. On most Android builds, opening Settings → About phone and waiting a moment triggers a check.
5. Reset network settings. Clears stale carrier state and forces the configuration to be re-read. You will need to re-enter Wi-Fi passwords.
6. Reseat the SIM. Marginal contact after any state change produces registration failures that look random.

Confirm whether it worked by checking IMS registration rather than by making a test call — a call can connect over a fallback path and look fine while VoLTE is still broken. VoLTE Check reads the registration state directly.

If the toggle is gone entirely

This is the meaningful case, and it is worth being straight about: a missing VoLTE toggle is not a settings problem.

Android shows the switch only when the carrier configuration permits VoLTE for this network and this device model. If the update shipped a configuration that no longer lists your model, no amount of menu-digging or factory resetting will bring it back — a factory reset restores the same configuration you already have.

What actually helps:

• Ask your carrier whether your exact model is still supported. Model numbers change between regional variants; give them the number from Settings → About phone, not the marketing name.
• Request a newer SIM. Free at most carriers, and it resolves a surprising share of provisioning-side cases.
• Check whether a further update is available. Where a regression is widespread, manufacturers do sometimes ship a fix.

The guide to enabling VoLTE covers what a missing toggle means in more depth, and the troubleshooting guide covers separating device, provisioning and whitelist causes.

Custom ROMs

If you flashed a custom ROM or took an AOSP-based update, VoLTE disappearing is expected rather than surprising. Carrier configuration is frequently absent from custom builds, and the modem firmware may not match what the carrier expects.

This is not something a setting fixes. Some ROM communities ship VoLTE-enabling patches, but they are specific to a device and carrier and any subsequent update can undo them.

Why calls may still work but sound worse

If VoLTE broke but calls still connect, your carrier still has 2G or 3G available and you have fallen back to it. You will notice narrower audio, slower connection, and data dropping during calls.

Where 3G has been switched off — most of the US, and increasingly elsewhere — there is no fallback and calls simply fail. That is why the same update can be a minor annoyance on one network and a dead phone on another. VoLTE vs 4G explains the distinction.

Frequently asked questions

Why did VoLTE stop working after a software update?

Updates replace the carrier configuration that tells Android VoLTE is permitted for your network and device model. If the new configuration no longer lists your model, or the modem firmware changed, VoLTE stops being offered.

How do I get VoLTE back after an update?

Toggle airplane mode, restart, confirm the toggle is still on, then check for a carrier settings update and reset network settings. If the toggle has disappeared entirely, the fix is with your carrier rather than on the phone.

Will a factory reset fix VoLTE after an update?

Almost never. A reset restores the same carrier configuration the update installed, so if that configuration is the problem, resetting changes nothing. Try a network settings reset first — it clears the same local state without wiping the device.

The VoLTE option disappeared from settings after updating. How do I get it back?

You cannot add it yourself. Android only shows the switch when the carrier configuration permits VoLTE for your device on that network. Contact your carrier with your exact model number and ask whether it is still on their supported list.

Why did VoLTE break after I flashed a custom ROM?

Custom ROMs frequently lack the carrier configuration that enables VoLTE, and may ship different modem firmware. This is expected behaviour rather than a bug, and any fix depends entirely on the ROM and device.

My calls still work but sound worse since the update. Why?

You have most likely lost VoLTE and fallen back to 2G or 3G, which use narrowband audio. Where the carrier has retired those networks, calls fail outright instead of sounding worse.