just go to the 2nd post of Scottys noob friendly root guide-start to finish
and follow the directions starting at method #2)"full ruu" method to unroot
when launching the recovery,make sure the image name in the fastboot boot
command matches the exact name of the image in your miniadb_vigor folder.
is given as an example,but your recovery may be named slightly different.
the generalized command is:
fastboot boot exactrecoveryname.img
also,make sure the recovery youre trying to launch is an .img,and not a .zip file