Samsung Galaxy S21 5G SM-G991B 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: G991BXXS3BULC_G991BOWO3BUKG_ZTO_4File.zip Country: Brazil File Size: 6.42 GB Android Version: 11 Flash Tool: Odin Download Tool How to Flash (install): Follow Tutorial Get Link