Download InFocus M5s official stock rom from the link below and follow the instructions after download link to learn how to flash.
The firmware is a card brush package. Which means it can only be flashed from your phone’s storage (sdcard).
If you don’t know how to flash or install the firmware from your sdcard, after downloading the firmware from the link below scroll down to find flashing instructions.
File Name: update.zip
Size: 1.02 GB
Android version: 7.0
Firmware Link: Download
How to flash InFocus M5s firmware
After downloading the the firmware from above link click here to follow flashing instructions.