You're looking for firmware for the TCL 30 SE. Here are some general steps and resources that might help:
Fix Bugs: Squash those annoying little glitches you’ve been noticing. firmware tcl 30 se
Perform a Hard Reset via Recovery Mode (Hold Power + Volume Up) or use the PC tool to "Repair" the firmware. Download fails mid-way You're looking for firmware for the TCL 30 SE
Also note the Baseband Version – this is specific to your cellular hardware. Keep a screenshot of this page before flashing anything. how to update
This guide covers the current software status, how to update, common issues, and firmware-related technical details.