a20s a30s a50 a51 a71 android android 9 android 10 android 10 update android 11 app at&t ayuda binary bootloader boot loop brazil csc csc change csc code downgrade download firmare firmaware firmware firmware update flash flashing galaxy galaxy a6 galaxy a21s galaxy a71 galaxy s7 galaxy s9 galaxy s9+ h3g help me j7 prime lte only network note 9 note9 note 9 firmware note 10 plus note10+ sm-n975u odin odin fail one ui 2.0 ota region rom s7 edge s9 plus s9+ s10 s10+ s20 ultra s20+ samsung samsung s8 security sm-g930f software software update tablet unlocked update updates upgrade verizon