Jetson Nano Recovery Mode

I only have micro USB power (J28)
I read this manual and refer to this site below but this manual based on Power Jack(J25)

I think that only J28(micro B USB) works as USB Device when SDKmanager works on, right?

is it possible to go recovery mode by using micro B USB power(J28)?

If the Jetson gets enough power via the USB B connector to run normally then yes. I just tested it. Tip: If you unplug the USB cable then put a jumper the recovery pins AND on J48 then plug the USB cable back in again, you can get everything ready then just remove the J48 jumper and the Jetson will start in recovery mode.