Linked are a Youtube video on how to replace the back glass for that specific model, but doing a quick scroll through it I'd definitely recommend using the technique and tools shown in the IFixIt link that shows a breakdown of the P30 Pro as using the long, bare razor blade like they did is dangerous to both you and the phone itself. [br]
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You're responsible for your own device, repairs, and safety but best of luck and let me know if you get that replaced successfully![br]
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https://www.youtube.com/watch?v=szbUcw27-X0&ab_channel=MOBILESERVICE[br]
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