Below is the direct link to download the Wiko Rainbow UP Stock Firmware (flash file) from GoogleDrive. Firmware contains Flash Tool, Driver and instructions.
How to Flash
Step 1: Download and extract the stock firmware on your computer.
Step 2: After extracting you will find the EXE file that contains the Firmware and Flash Tool.
Step 3: Simply follow the screen instructions to install the firmware on your Wiko Mobile.
[*] Take a Backup of your personal data before flashing or installing the firmware on your smartphone. As this helps you to recover the personal data whenever any thing wrong happens.