Flashing official firmware is the only safe way to unbrick a device after a failed software modification. How to Update Your TCL 30 XL 4G Firmware
There are two primary ways to ensure your device is running the latest official software: 1. Wireless Update (FOTA) Firmware TCL 30 XL 4G
Updates deliver the latest Android security patches to protect your personal data. Flashing official firmware is the only safe way
The easiest method is Firmware-Over-The-Air (FOTA), which requires no computer. TCL 30 XL - Full phone specifications - GSMArena.com Firmware TCL 30 XL 4G