Unhappy [Q] i see the recovery droid and then recovery stops and reboots???

ive done as instructed, and just as i see the fruit of my labors....my reward is taken.. wtf!! I FINALLY GOT M Y LG L90 TO REBOOT IN TO RECOVERY, and the revovery droid pops upthen recovery stops and just rebooots
here are my steps
  1. adb from sdk platform tools
  2. adb devices
  3. adb shell
  4. reboot recovery

what happen? help