How to change Android system boot slot form A to B

fastboot — Debian testing fastboot get active slot So i decided to flash twrp into a boot slot via fastboot then, i set the active-slot to that but then I still don't get twrp idk why Now, I can get into fastboot change slot From there you can run fastboot getvar current-slot to see which slot you are on And you can change slots using fastboot --set-active=the slot

fastboot get active slot It may not flash TWRP as there is no active slot not bootable) If it is a slotted device in Fastboot run the command: fastboot getvar