I am using Xiaomi phone, in which I have got a hardware error(sound problem), which may be a bug. Then I serviced my phone. Now it functions well. If I restore my previous backups, should it result a hardware error again? Thanks in advance.
No backups are not connected to hardware problems. Hardware means physical part/s of the device. The backup is software, by that I mean the non-physical part (or correctly data).
If you want detailed, please write us what was the problem with you phone. What did the service sad about the problem.