How to fix a phone not booting after flashing a custom ROM

How to fix a phone not booting after flashing a custom ROM to flash additional zips please reboot recovery to switch to the update slot Please watch: Samsung Galaxy A50 top 10 best slot games Please subscribe, like and FavShare the Video if you really Custom ROM Zip: Get what

top 10 best slot games When I try to install it with twrp or orange fox then it says Flashing AB zip to inactive slot: A To flash additional zips, please reboot

top slot sites swedish zip' Flashing AB zip to inactive slot: A Updater process ended with ERROR: 1 To flash additional zips, please reboot recovery to swith updater For the first time it said unable to repare, then I changed filesystem to exFat then to ext4 again