Firmware — T.mt5522.81

This is common in low-cost tablets. The manufacturer cloned the build.prop file. Your actual chip is MT8163, and you should search for firmware specifically for MT8163_T.mt5522.81 (a cross-port). Use CPU-Z to verify.

No firmware is perfect. Here are the most frequently reported issues with T.mt5522.81 and how to fix them. T.mt5522.81 Firmware