Your desire to understand proves that you are a power user who wants full control over your device. Whether you are updating to fix a touchscreen glitch, reviving a dead phone, or simply ensuring you have the latest security patch, the golden rules are:
Before attempting any update or download, you should know what version is currently running on your device. This helps you determine if a new update is available. Firmware TCL 40 NxtPaper
A complete firmware package includes: