How to automate slot selection after android AB-Update

How to automate slot selection after android AB-Update fastboot get active slot Boot your smartphone into Fastboot Mode · Now, connect your smartphone to the PC using a USB cable · Open a Command Prompt, Terminal, or fastboot change slot On AB devices, flashed slot is set as active Secondary images may be flashed to inactive slot flash PARTITION Flash given partition, using the

fastboot change slot I was able to fix this with fastboot --set-active=a followed immediately by fastboot flash boot and all the other partitions

fastboot_ error_ failed to identify current slot I hoped I could find a phone that had an sd card slot and headphone jack but active on the screen, in the name of battery my Bluetooth connection buffers  查詢目前使用那個槽， 看目前的slot是a還是b，一般都是a。1$ sudo fastboot getvar current-slot 參考 adb