Owners of the popular fitness tracker Xiaomi Mi Band 4 often face a situation where the device suddenly stops syncing with the iOS operating system.This can happen after updating the smartphone operating system, changing the Bluetooth tariff plan, or simply because of a software failure in the work of the companion app. The lack of communication between gadgets makes it impossible to receive notifications, track activity and update the firmware, which turns a smart bracelet into a regular watch.
Before you panic and carry the device to the service center, you need to perform a number of diagnostic procedures. In most cases, the problem is not a hardware breakdown of the tracker, but a conflict of software settings or a crowded app cache. The most common reason for failure is the simultaneous connection of the bracelet to the old Mi Fit application (Zepp Life) and the new control system on the iPhone. Understanding the nature of the failure allows you to eliminate it in a few minutes without losing data.
What we do next depends on where the communication breaks down, whether it's in the device search phase, when you try to pair or when you're transferring data, and we'll look at all the scenarios that we can do, from simple reboots to clearing Bluetooth profiles completely, and it's important to follow the steps consistently to eliminate human error and configuration errors.
Primary Diagnosis and Compatibility Checking
The first thing to do is make sure your smartphone is technically capable of supporting the fourth version of the bracelet. While the iPhone 5S and newer models are officially supported, older versions of iOS can cause conflicts. Make sure your device has an operating system at least iOS 10.0 installed, as earlier versions may not have the necessary Bluetooth Low Energy drivers.
If the charge level is critically low, the Bluetooth module may operate unstable or go into power saving mode, making the device invisible to scanning. Put the bracelet on charge for at least 15-20 minutes before trying to reconnect.
Remove your smartphone and bracelet from powerful radiation sources such as microwave ovens, Wi-Fi routers or USB 3.0 running ports that can create noise in the 2.4 GHz range.
It's important to check if the tracker is connected to another device.The Mi Band 4 can only maintain an active connection to one smartphone at a time.If the bracelet has previously been used with an Android smartphone, it can automatically try to reconnect with it, ignoring requests from the iPhone.
Bluetooth settings and removing old profiles
System level interaction in iOS requires purity of pairing profiles. If the phone has a tail from a previous connection attempt, the new initialization will be blocked. Go to the iPhone settings, select the Bluetooth partition and find the Mi Band 4 entry in the list of devices.
If you have such a record, click on the information icon (the blue letter "i" in the circle) and select "Forget this device." This action will delete the encryption keys and reset the connection settings for this gadget. After that, it is recommended to completely turn off Bluetooth with the switch in the settings, wait 10 seconds and turn it on again.
⚠️ Note: Do not use Forget Device if the bracelet is far from the phone or off.This may cause the profile to remain in the system in the status of "error", and you need to completely reset your iPhone network settings.
Once the list is cleared, you sometimes need to reboot the communication module itself, which you can use flight mode, turn on Air Mode for 15 seconds, then turn it off, and this will force you to restart all the radio modules on your smartphone, including NFC and Bluetooth, which often solves the problem of frozen scanning.
☑️ Bluetooth Preparation Checklist
Work with Mi Fit and Zepp Life
The main tool for managing the tracker is the app. At the moment, the Xiaomi ecosystem is moving to the Zepp Life app (formerly Mi Fit), and older versions may not work properly with new versions of iOS. Make sure that the App Store has the latest available version of the program installed.
Often, the problem is solved by completely reinstalling the application. When you delete the program, the training data can be lost if it was not synced to the cloud, so check the sync status in advance. After you delete the application and re-install it, you need to log in to your Mi Account again.
There are also hidden settings inside the app that can affect connectivity, so go to the device profile and check if there's a visibility restriction, and sometimes adding the bracelet over the app interface helps, rather than through the Bluetooth system settings.
What to do if the app does not see the bracelet?
It is important to give the application all the necessary permissions. When you first start or after updating iOS, the system may request access to Bluetooth, notifications and geolocation. Failure to any of these points can lead to unstable operation.
Reset bracelet settings to factory
If the software methods on the smartphone side did not help, you need to reset the tracker itself.This will return the device to its original state, removing all accumulated configuration errors. → Unbind (Additional) → Untie).
Once confirmed, the bracelet vibrates and reboots, the screen goes out, and the device goes into pairing standby mode, and you can now try to find it through the iPhone app as a new device, which is effective in 90% of software failures.
| Action. | The result | Data retention |
|---|---|---|
| Reboot (Reboot) | Temporary removal of freezes | Preserve. |
| Unbind (Unbind) | Breaking the phone connection | Saved on the bracelet |
| Reset (Factory Reset) | Complete removal of settings | Removed |
| Zero discharge | Hardware reset of the controller | Partly lost. |
There's also a method of "hard" resetting through full discharge: leave the bracelet on until it's completely discharged and turned off. Then put it on charge and, not turn it on, try to initiate the connection. Sometimes this helps to reset the errors of the power controller.
Updating firmware and system software
Incompatibility between the bracelet firmware and the app version is a common cause of problems. If the bracelet is still able to connect at least for a short time, immediately check for updates. In the device profile in the application, click on the firmware version.
The firmware update process is critical to stability. New firmware versions often contain patches to be compatible with new iOS versions. Don't interrupt the upgrade process and keep your phone near your wristband.
💡
If the update is suspended on 99%, Don't panic. Leave the bracelet on the charger next to the phone on the 15-20 Often the process ends in the background, and the bracelet will reboot itself.
It’s also worth checking out the iPhone operating system itself. Apple regularly releases security patches and enhancements for the Bluetooth stack. Go to Settings → Main → Software Update and make sure you have the current version installed.
⚠️ Warning: Never try to update the bracelet firmware if it is less than 20% charged.Stop recording data during an update can "brick" the device, making it unusable.
Specific iOS 15/16/17 issues and newer
With the release of new iOS versions, Apple is tightening its privacy policies, including app tracking and background features that require explicit user permission. If you recently upgraded your iPhone, check your privacy settings.
Go to Settings → Privacy → Location and make sure that the Mi Fit (Zepp Life) application has an “Always” or “When in use” resolution. Without this, the application will not be able to maintain a permanent connection to the bracelet to synchronize data in the background.
💡
A key problem with new iOS is aggressively closing the background apps: add the Mi Fit app to the exclusion list or use desktop widgets to make the app appear active.
Another feature is the notifications. In newer versions of iOS, the notification center works differently. Make sure that the Bluetooth settings for the Mi Band 4 device do not select Headphones or Other in the Device Type section, but the fitness tracker or similar profile if the system allows you to manually select it.