Here you can download MediaTek MT6750 based Scatter Stock Firmware for the Symphony Z9 Android device. The downloadable file High Compressed in an archive, You will get the Flash File after extraction. Included contains Flash Tool, USB Driver, and how-to Flash manual instructions.
[*] Chipset: MediaTek MT6750.
[*] Driver: MTK USB Driver.
[*] Flash Tool: Smart Phone Flash Tool.
Get Firmware for Symphony Z9 (Flash File)
Build Number: Z9_HW1_V0508
Build Description: L6158_DL61581_SYMPHONY-Z9_C0508
Android Version: v7.0 (Nougat)
Download Size: 1.43 GB
[*] Backup: During the flashing process SP Flash Tool will erase user data from the phone. So you need to backup for restoring those files on your device.
[*] Device Information: The Symphony Z9 phone powered by MediaTek MT6750 CPU. So you need to use MTK SP Flash Tool and MTK USB Driver to flash Firmware on this device.
[*] Flashing Information: You should use only the “Firmware Upgrade” option in SP Flash Tool when you want to reinstall or upgrade the Software of your device. – “Format + Download” option only for Engineering Purposes.