Here you can download Qualcomm MSM8929 based QFIL Stock Firmware for the Micromax E457 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: Qualcomm MSM8929 Snapdragon 415.
[*] Driver: Qualcomm USB Driver / ADB Fastboot Driver.
[*] Flash Tool: Qualcomm Flash Image Loader / ADB Fastboot Android SDK Platform.
Firmware for Micromax E457
Build Number: MMX_E457_SW_V03_HW_V1.0_13052016
Android Version: v5.0.2 (Lollipop)
Download Size: 843 MB
[*] Backup: During the flashing process Qualcomm Flash Image Loader tool will erase user data from the phone. So you need to backup for restoring those files on your device.