Android Recovery
samsung/a20ub/a20
10/QP1A.190711.020/A205GUBU5BTD2
user/release-keys
Use volume up/down and power.
Reboot to bootloader
Apply update from ADB
Apply update from SD card
Wipe data/factory reset
Wipe cache partition
Mount /system
View recovery logs
Run graphics test
Run locale test
Power off