Symphony B50 Stock Firmware (Flash File) The Flash File will help you Upgrade, Downgrade, or re-install the Stock Firmware (OS) on your Mobile Device. In addition, the Flash File (ROM) also enables you to repair the Mobile device if facing any Software Issue, Bootloop Issue, IMEI Issue, or Dead Issue. File Name: Symphony_B50_MT6261_MIRA.zip File Size: 27 MB Flash Tool: Miracle Tool How to Flash (install): Use Miracle Box Software to Flash or install the firmware. (Mediafire)