How to Fix Xiaomi HyperOS Audio Routing Failure During Calls

Audio routing on Xiaomi HyperOS controls which output device — earpiece, speaker, or connected headset — receives call audio. When routing fails, calls connect normally and the other party can hear you, but you hear nothing or audio plays from the wrong output entirely. This is a distinct problem from a faulty microphone and has its own set of causes: a corrupted telephony audio policy file after a HyperOS update, a Bluetooth or wired headset session that did not close cleanly, or the AudioFlinger service crashing in the background. The fixes below target the audio routing stack directly.

Steps

1. Rule out a stuck audio session from a previous headset or Bluetooth device.

   If a Bluetooth headset or wired earphone was connected when the problem started, the audio route may be locked to that device even after disconnection. Toggle Bluetooth off and on, then unplug any wired accessory. Dial *#*#0673#*#* or a test number and check whether call audio now comes from the earpiece. If yes, unpair the last Bluetooth device used and re-pair it cleanly.

2. Clear the Phone and InCallUI app cache.

   Go to Settings → Apps → Manage apps. Search for Phone (the system dialer) and tap Clear cache. Repeat for In-call screen (InCallUI) if listed separately. Restart the phone and make a test call. Cached audio session state in these apps is a common cause of routing lock after an OTA update.

3. Reset all audio output settings via the Sound troubleshooter.

   Go to Settings → Sound & vibration and scroll to the bottom. On HyperOS 3, tap More sound settings → Reset to defaults if available. Alternatively, dial *#*#64663#*#* to open the CIT menu, navigate to Audio → Receiver test, and run the earpiece test. A passing result confirms the earpiece hardware is fine and the fault is software-side.

4. Use ADB to restart the AudioFlinger service without rebooting.

   Enable USB debugging under Settings → Additional settings → Developer options. Connect to a PC with ADB installed and run:

   adb shell stop media
adb shell start media

   This restarts the Android media server — which hosts AudioFlinger — and clears any hung audio routing policy without a full device reboot. Make a test call immediately after.

5. Repair HyperOS system files if the issue persists after all software fixes.

   A corrupted audio_policy_configuration.xml or telephony audio HAL file introduced by a failed OTA update cannot be fixed through settings alone. Download the correct stock fastboot ROM for your Xiaomi model and flash it using Mi Flash Tool with the save user data option to repair system partitions while preserving personal files where possible.

Common Issues and Fixes

• ADB commands run but problem returns after next call — likely cause: a rogue app is re-locking the audio route each call — fix: boot into safe mode, make a test call; if audio works in safe mode, a third-party app (often a call recorder or accessibility tool) is the culprit.
• CIT earpiece test fails with no sound — likely cause: earpiece hardware damage — fix: stop software troubleshooting; contact Xiaomi service center for earpiece replacement.
• Mi Flash Tool "save user data" option still causes data loss — likely cause: the update requires reformatting the userdata partition — fix: back up with Dr.Fone or Mi Cloud before flashing any ROM.
• Issue only occurs on VoIP calls (WhatsApp, Teams) but not regular calls — likely cause: VoIP app audio session management conflict — fix: clear cache of the specific VoIP app and revoke then re-grant its Microphone and Phone permissions.

Quick Tips

• Test with the CIT menu first: Dialing *#*#64663#*#* and running the Receiver (earpiece) audio test takes 30 seconds and immediately tells you whether this is a hardware or software problem — skip straight to service center if the hardware test fails.
• Speakerphone as a workaround: If you need to make urgent calls while troubleshooting, use speakerphone mode — the speaker output path is separate from the earpiece routing chain and is usually unaffected.
• Check for conflicting call recorder apps: Third-party call recording apps hook into the telephony audio stack and are a leading cause of audio routing failures on HyperOS 3. Disable them one at a time in safe mode to isolate the conflict.