Xiaomi's wireless headphones are some of the most popular gadgets, thanks to a combination of price, sound quality and functionality. But even proven models like the Redmi Buds 4 Pro, Xiaomi Buds 3T Pro or Mi True Wireless Earphones 2 have a typical problem: the left and right earphones stop syncing with each other, one can connect to the phone, and the second can be silent, flash red or not respond at all. In some cases, the sound comes from only one earphone, and the second just falls off after a few seconds.
The causes of this malfunction are software-based (firmware failure, Bluetooth conflict) and hardware-based (battery discharge, contact damage). In this article, we will look at all possible ways to restore sync, from basic actions like rebooting to hidden functions in the engineering menu. You will also learn how to distinguish a temporary glitch from a serious breakdown and when to contact the service center.
Why Xiaomi headphones are out of sync: 5 main reasons
Before you start repairing, it is important to understand what caused the problem, and most often the fault is:
- 🔋 A discharged battery in one of the headphones (even if the indicator is green, the real charge can be critically low).
- 📱 Bluetooth conflict on a smartphone or other device that has headphones connected.
- 🔄 Firmware failure after automatic update or incorrect disconnection.
- 🎧 Mechanical damage: oxidation of contacts in the case, falling or getting moisture.
- 🔧 Incorrect settings in the Mi application Fit/Xiaomi Wear (for example, activated Monosound mode»).
In 70% of cases, the problem is solved software-free without disassembling or replacing parts, but if the headphones stopped synchronizing after a fall into the water or a heavy impact, you will most likely need repairs in the service, and you should also be alert if one of the headphones constantly overheats or makes extraneous noises - these are signs of damage to the battery or speaker.
Method 1: Basic reboot of headphones and smartphone
Start with the simplest, forced reboot of headphones, which helps 30 to 40 percent of the time, especially if you've had a software update or abrupt Bluetooth shutdown.
1.Put both headphones in the case and close the lid
2 Wait 10 seconds, then open the case
3.Push and hold the reset button (usually located on the back of the case) for 15-20 seconds until the indicator flashes red and white.
4.Close the case, wait 30 seconds and remove the headphones
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If your headphones are still out of sync after rebooting, try restarting your smartphone (or other device they're connected to). Sometimes the conflict arises from a temporary failure in your phone's Bluetooth module. On Android, you should also clear your Bluetooth cache:
- Open Settings → Applications → All applications.
- Find Bluetooth in the list and select it.
- Press Warehouse. → Clear the cache.
- Reboot the phone.
⚠️ Warning: Do not click Clear Data in Bluetooth settings – this will delete all saved devices and they will have to be reconnected.
Method 2: Resetting headphones to factory settings
If a simple reboot doesn't work, the next step is a hard reset, which will delete all user settings, including connection history, and return the headphones to a "out of the box" state, which differs depending on the model:
| Model headphones | How to reset |
|---|---|
| Redmi Buds 3/4/5, AirDots | Place the headphones in the case, open the lid. Press and hold the button on the case for 20 to 30 seconds until the indicator flashes red and white alternately. |
| Xiaomi Buds 3/4 Pro, Mi Earbuds | Press both headphones (touch panels) at the same time and hold for 10-15 seconds until you hear the reset beep. |
| Mi True Wireless Earphones 2 | Place the headphones in the case, then press and hold both touchpads on the headphones for 15 seconds. |
After reset, the headphones will automatically go into pairing mode (the indicator will flash white). Connect them to the phone again via Settings → Bluetooth. If sync is not restored, move to the next method.
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Before reset, check the case charge — if it is discharged below 20%, the procedure may not work. Connect the case to charge for 10-15 minutes and try again.
Method 3: Update the firmware via Mi Fit/Xiaomi Wear
The oversussing often results from outdated or damaged firmware, and the manufacturer regularly releases updates to fix plug-in bugs to update the headphones.
- Install the official app: For Redmi Buds - Mi Fit (available on Google Play and App Store). For Xiaomi Buds Pro - Xiaomi Wear.
Connect the headphones to the phone via Bluetooth.
Devices
Profile
Settings of the device → Updating the firmware
If the update is available, follow the on-screen instructions, do not turn off the headphones or close the app during the process, which can lead to a complete loss of sync, and on average, the update takes 3-5 minutes.
What to do if the update is suspended?
Method 4: Checking the contacts of the case and headphones
If the software methods didn't work, the problem could be mechanical damage, and it's often the fault of:
- 🔌 Oxidized or contaminated contacts in a case or on headphones.
- 🔋 Bloated battery in one of the headphones (leads to poor contact).
- 💧 Getting moisture (even if the headphones have protection) IPX4, Long-term exposure to water can cause corrosion).
To check the contacts:
- Take out the headphones from the case and inspect the metal contacts (usually 3-4 points on the bottom of the earphone and inside the case) and they should be clean, without green plaque or dark spots.
- If the contacts are contaminated, gently wipe them with a cotton swab soaked in alcohol (do not use acetone or other aggressive solvents!).
- Check if the headphones fit tightly into the case - if one of them staggers, the lock may have been broken.
Also, try changing the headphones to the box, and if the headphone that's not working then starts to function and the other one goes off, the problem is exactly in the contacts or the battery.
⚠️ Warning: If you notice one of the headphones swelling (the body is deformed, the lid is not tightly closed), you can not continue using it - this is a sign of a faulty battery that may ignite.
Method 5: Manual pairing of headphones (for advanced users)
If standard methods don’t work, you can try to force the headphones to sync manually through an engineering menu, which is suitable for models on a Qualcomm chip (for example, Redmi Buds 4 Pro or Xiaomi Buds 3T Pro).
You'll need:
- Android smartphone (on the iPhone this method does not work).
- The nRF Connect app (download to Google Play).
Instructions:
- Open nRF Connect and connect to the headphones (they should be in search mode).
- Go to the Unknown Service tab and find the service from UUID 0000fff0-0000-1000-8000-00805f9b34fb.
- Select the characteristic 0000fff1... and send the command 01 00 (without quotes).
- The headphones should reboot and sync.
If this method seems too complicated, you should contact the service. The wrong commands in the engineering menu can finally kill the headphones.
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Manual pairing is an extreme method, and only use it if other methods have not worked and you are confident in your actions.
Method 6: Contact Xiaomi Service Center
If neither of these methods has restored synchronization, it's probably a hardware problem.
- 🛠️ Official service is the best option if headphones are guaranteed.
- 💰 The cost of repair depends on the model: Redmi Buds 3/4 — battery-change ~1 500–2 000 ₽, fixture ~1 000 ₽. Xiaomi Buds Pro – Diagnostics ~500 ₽, surcharge ~3 000 ₽.
- ⚠️ Unofficial workshops can offer cheaper, but the risk of getting a “cat in a bag” is high – often using unoriginal parts.
Before the service visit:
- Take photos of your headphones and case (especially if there are external damages).
- Bring a check or a warranty card (if saved).
- Check by phone whether they are repairing your model – some services work only with phones.
If headphones are older than 2-3 years, it is sometimes cheaper to buy new ones than to repair old ones. ~3 000 ₽, The repairs can cost half of that amount.