I've had my Xiaomi Mi 5s for 2 years and 9 months and, of course, the battery is not what it is. Since I thought I'd pass it on to my mom when I get something new, I got a replacement battery from eBay and, having watched 4 YouTube videos on disassembling this particular phone, I gave it a go. What went wrong: After removing the two T3 torx screws, when I tried to use a suction cup to pull the bottom section from the back cover, I pulled off just the screen instead. How I fixed that: I reattached the screen with some thin double sided tape and then used a plastic pry tool and a "guitar pick" to remove the cover, unscrewed some protective metal sheet and unplugged the battery. Then I tried to remove the battery, which was held in by some really strong tape. What went wrong: I applied too much local pressure on the battery while trying to pry it out and it caught fire, still firmly attached to the phone! How I fixed that: I threw it on the kitchen counter and covered it with a small glass bowl. I tried to seal the edges with some tea towel and waited a bit. Then, as the bowl kept filling with smoke, I remembered that Li-Ion batteries can burn without oxygen, so I slid it into a pot and took it out to the balcony. There I left it for a few minutes, and then it occurred to me to check if the heat loosened the adhesive holding battery. It did. I carefully (so as not to burn myself) removed the battery from the phone and left it outside. The phone itself seemed fine, other than that it was scorching hot, so I left it to cool down and then installed the new battery and powered it on. It works! More luck than smarts, I guess. It is a rather simple procedure, but if you've never done anything like it, you have good chances of making a mess. And out of the 4 videos I watched, even though they are generally speaking similar, after my own experience, I can say that only one is actually really good.