if you see something like:gpg: Signature made Thu 15 Sep 2016 06:15:44 AM PDT using RSA key ID 16B500A8gpg: Can't check signature: public key not founderror: could not verify the tag 'v1.12.17-cr2'then you need to update your depot_tools checkout. wherever you made it, go in there and run `git pull`.-mike