How to fix Xiaomi earbuds when only one side works

- First, put the earbuds in their charging case. Then, unpair the headphones from your mobile phone.

- Remove the two earbuds from their case and press their physical button or touchpad (depending on the model) for five seconds to completely turn them off. You will notice that a red light appears before this happens.

- Next, simultaneously press the physical buttons or on the touchpad of each headset again for approximately twenty seconds. During this period you will notice a series of blinks. When you see the third set of blinks, release the buttons and return the earbuds to their charging case.

- Finally, proceed to re-pair the headphones with your mobile phone.

https://en.alfanotv.com/smart-home/how-to-fix-one-side-of-xiaomi-earbuds-when-not-working/