# fastboot set_active command does not exist

I am trying to root my Xiaom mi a2 phone. But i am stuck on changing the active partition. When i enter "fastboot set_active b" it doesnt execute the command. Instead i get a list off all available commands which doesnt contain an option to change the active partition.

Console-Output

I am following this tutorial: Tutorial

• Please copy-and-paste the fastboot output instead of the screenshot. Screenshots aren't searchable, so they don't let people find your question. – Dan Hulme Oct 27 '18 at 14:24

First you need the actual fastboot, e.g. 1.4.3 (from link in the other answer). Then the correct command is:

fastboot --set-active=a


or:

fastboot --set-active=b


In the help (fastboot help) you can read in fastboot version 28.0.3:

--slot <slot>                          Specify slot name to be used if the
device supports slots. All operations
on partitions that support slots will
be done on the slot specified.
'all' can be given to refer to all
slots.'other' can be given to refer to
a non-current slot. If this flag is not
used, slotted partitions will default
to the current active slot.

-a, --set-active[=<slot>]              Sets the active slot. If no slot is
provided, this will default to the
value given by --slot. If slots are
not supported, this does nothing.
This will run after all non-reboot
commands.


I tried a lot of things, nothing worked until i came across this: minimal-adb-and-fastboot-tool-for-windows

Now i was able to set the active partition and install the root. I got no errors and everything seemed fine but i still had no root access. I found this tutorial: guide-how-to-root-xiaomi-mi-a2-magisk and it worked for me.

Well, the fastboot you are using is outdated. You need to install the latest platform-tools from Android SDK which has the latest fastboot binaries.