What happens when we try to flash custom ROM via stock recovery

I installed manager directly on android stick and patched the stock recovery image Then i rebooted into recovery by only pressing the Reset

to install the Android 13 Developer Preview 2 on Mi A2 So, after unlocking the bootloader and

tower tumble slot Instead, go back to the main menu, choose Reboot, change the slot ( if it says Current Slot: A, tap Slot B, vice versa Quit the menu and tap

toto 5d slot done Devices on super may not mount until rebooting recovery To flash additional zips, please reboot recovery to switch the updated slot