Manual flashing carries a risk of "bricking" the device and will erase all user data. Common Firmware Issues & Recovery How to Download Firmware for ZTE Blade L9?, How To
The device uses a Spreadtrum/Unisoc chipset. For manual flashing, you typically use the SPD Upgrade Tool
In these cases, a fresh installation of the (the official software from ZTE) is the only reliable solution.
Updating the firmware on your ZTE Blade L9 is crucial for several reasons:
