Xiaomi’s smartwatches suddenly lose connection to their phones, a situation familiar to many wearable electronics owners: the screen goes out, notifications stop coming, and the activity tracker does not update pulse or step data. This happens on both devices with the Wear OS operating system and classic fitness bracelets that use proprietary communication protocols through the Mi Fitness or Zepp Life app.
The main reason lies in the aggressive energy saving policy of modern versions of Android and iOS.The system seeks to extend the life of the smartphone by forcibly closing background processes and breaking connections to peripherals that seem inactive. However, the problem may be deeper, from interference in the air to software bugs in the firmware of the tracker itself.
Understanding how Bluetooth Low Energy (BLE) works helps you realize that a communication break is often not a breakdown, but the result of a configuration conflict. The user needs to conduct a comprehensive diagnosis, eliminating software errors and physical obstacles.
Aggressive energy saving and battery optimization
The most common reason why Xiaomi Mi Band or Amazfit shut down is the charge saving settings on the smartphone. Android, especially in the MIUI and HyperOS shells, seeks to "kill" any process that consumes energy in the background. The companion app responsible for synchronizing falls into this list of victims.
You have to manually configure exceptions for Bluetooth services and watch management applications, without which the system will regularly force the sync service to stop, which looks like a permanent disconnection, which is not a bug, but a feature of modern mobile platforms.
⚠️ WARNING: If you use third-party memory cleaners or antiviruses, they can block Bluetooth services even more aggressively than the system itself.
To solve the problem, go to the battery settings and find a list of working applications. You need to find Mi Fitness, Zepp Life or Google Fit and change the mode to "No Limits." Also check the autostart settings so that the system does not unload the process from memory after rebooting the phone.
Often users forget that the Bluetooth module on the phone can also go into sleep mode to save energy. In some smartphone models, there is a hidden option for Bluetooth, which is worth activating in the developer menu if standard methods do not help.
Problems with Bluetooth version and drivers
Connection instability is often caused by incompatibility of Bluetooth protocol versions. Older watch models running on Bluetooth 4.0 or 4.2 may have difficulty connecting to the latest flagships with Bluetooth 5.3 or 5.4 modules. Although the standard provides backward compatibility, in practice this does not always work perfectly.
Bluetooth drivers on a smartphone may not work properly, especially after a major system update, and the connection cache may overflow or become corrupted, leading to handshake errors between devices, in which case a complete reset of the phone's network settings helps.
How to Reset Network Settings
Check how many devices are connected to your phone at once. If you have wireless headphones, a second tracker, a car headset and a smart home connected, the communication channel can be overloaded. Bluetooth has a limit on the number of active data streams, and the watch can simply be pushed out of the priority queue.
Sometimes the problem lies in the physical module of the smartphone, if the phone dropped, the Bluetooth antenna could move away from the contact, in which case the clock will turn off when the phone is in a certain orientation in space or at a distance of more than 1-2 meters, even if they used to hold communication at 10 meters.
Application conflicts and background processes
The clock control app installed on the phone is a bridge that should not be interrupted. However, there are many services on Android that can conflict over access to a Bluetooth adapter, such as apps to find lost things or scanners. QR-Codes can intercept control of the module.
The Mi Fitness or Zepp application requires full geolocation rights (even if the GPS is not in the watch, this is necessary for the BLE to work), access to notifications and background work, and if you accidentally disallow any of these parameters when updating the software, communication will break.
- 🔍 Check if another watch manager is running in the background (for example, you switched from Huawei Health to Zepp, but the first app remained active).
- 📱 Make sure the application has permission to "display on top of other applications".
- 🔄 Try clearing the companion app cache through your Android settings without deleting your account details.
In rare cases, the conflict is caused by antivirus software that treats the constant exchange of data packets with an external device as suspicious activity. If you use a corporate profile on your phone (MDM), the company's security policies can block continuous communication with wearable electronics.
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If you’ve recently updated your watch app or phone system, try restarting your smartphone. Often, after an update, you need to restart all system services to ensure that new drivers work properly.
Software failures of the firmware of the watch and phone
Software is a complex structure where a bug in a single line of code can cause a connection to drop. In Xiaomi and Amazfit devices, there are sometimes firmware errors that cause the Bluetooth module to reboot cyclically inside the watch itself, it looks like the phone is losing the device.
Check the firmware version on the watch. Often, manufacturers will issue patches that fix the connection stability issues. The update may not come automatically if the connection is unstable, creating a vicious circle. Try to bring the watch close to the phone and start checking for updates manually in the application.
| Symptoms. | Probable cause | Decision |
|---|---|---|
| The clock is off at night. | Power saving mode of the phone | Add an annex to the exceptions |
| Breaking up when leaving the house | Switching Wi-Fi to 4G/5G | Disable Wi-Fi Assist or analogue |
| The watch is not visible when searching | Hanging of the Bluetooth module | Reboot both devices |
| Communications are in, no data. | Synchronization error | Remove and re-create the pair |
If the problem occurred after the firmware update, it is possible that the new version of Android has a conflict with the current version of the watch software, in which case it remains to wait for an update from the watch manufacturer or roll back the phone system (which is more difficult).
If simple methods do not help, it is recommended to completely remove the application, restart the phone, download the latest version from the official store (Google Play or App Store) and set the watch as new.
Physical obstacles and radio interference
Bluetooth is running at 2.4 GHz, which is extremely oversaturated. It's the same frequency that home Wi-Fi routers, microwave ovens and wireless mice run. If your router is next to your bed or desktop, it can jam the clock signal, especially if it's in your jeans pocket.
Materials matter, too. Metal phone cases, magnetic insert cases, or even dense fabric can shield the signal. A person is essentially made up of water, which also absorbs radio waves. If you hold the phone in your left hand and the watch in your left hand, your body can shield the signal.
Check for new sources of interference in your environment. USB 3.0 cable (they cause severe interference in the 2.4 GHz range), connected next to the phone, or a new wireless device. USB-port on your computer or remove the Wi-Fi antenna extension extender away from the charging point of the clock.
Algorithm of complete reconnection of devices
When simple reboots don't work, you need a radical method -- a complete pairing reset -- that allows you to clear old encryption and handshake keys that might have gotten damaged, and you need to follow the steps in a strict sequence.
First, remove the device from the phone's Bluetooth menu. Don't just turn it off, click "Forget device" or the gear icon and select "Unpair." Then remove the device from the list inside the Mi Fitness or Zepp Life app.
☑️ Complete reset of connection
Once you reboot both devices, start the search again. When you first connect, the system will request confirmation of the code on the watch and phone screen, be sure to check the numbers. If the codes do not match or the request does not appear, repeat the reset procedure.
⚠️ Note: With a full reconnection, the activity history for the period when the clock was turned off may be lost if it did not sync with the server. Make sure that before resetting, you open the application and give it time for the last sync.
If that doesn't work, try connecting your watch to another phone, and if the other phone is stable, the problem is exactly the settings of your main phone, and if the clock is switched off everywhere, the Bluetooth module in the watch itself may be faulty.
Specificity of iOS and Android when working with Xiaomi
iPhone users are less likely to experience this problem, but it is more critical because of iOS's tight restrictions on background work.The system can "freeze" the Zepp Life app if you haven't opened it in a long time.In iPhone settings, it's important to allow background updates to the content for the watch app.
On Android, the situation is more diverse because of thousands of smartphone models. On pure Android (Pixel, Motorola), the problem is easier to solve. UI, Huawei EMUI Xiaomi MIUI/HyperOS Requires dancing with a diamond in the menu "Battery protection".
Xiaomi owners should go to the app Security → Battery → Settings and disable all aggressive saving modes. MIUI also has a hidden function "Stop Start", which you need to turn on to apply the watch manually, otherwise the system will not allow it to start the Bluetooth service when the phone starts.
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The stability of Xiaomi watches 90% depends on the correct settings of energy saving on the smartphone, not on the quality of the gadget itself.
It’s also important for iOS not to lock the screen too often at the time of initial setup, and sometimes removing and re-installing the companion app itself helps, as iOS often caches older device profile configurations.