How to Check and Change Current Active Slot on Android [Fastboot

try setting the slots again, without the space between -- It will return fastboot --set-active:a fastboot: unknown option – set-active:a

Open a Command Prompt, Terminal, or Powershell and then type the following command – fastboot --set-active=a or fastboot --set-active=b

fastboot get active slot slots ourselves using a Fastboot command Changing Android's Active Partition Slot

fastboot getvar currentslot I had to install Android 9 on both (You can check the active slot with fastboot getvar current-slot , and select a slot with fastboot --set