I have had a Mi 9 since August, 2019. In feburary, suddenly my phone started to randomly shut down, and I could not restart it sometimes. Once I could not turn on, just for half day, and then totally died.
I visited a phone service, who said it’s a motherboard issue (maybe charging IC), and it’s dead. I went home, put it on charger and IT WORKED. Worked till 2020 July (almost half year after it was said it’s useless).
Now it showed the android logo, then turned off. Sometimes it booted correctly, then turned off. It was a bootloop, but if I let it to loop a lot of time after half an hour it started. After few hours of totally perfect use, it died again. Then I flashed and used MiFlash. It could not be turned on. I could only reach fastboot (still loop). When battery drained, I visited services, all of them said it’s a motherboard issue.
Is it possible to die like this? I think it’s more likely battery doesn’t fit well or something.