So again just my understanding, so I could be wrong, but I believe it's more like ZTE creates / tests the software. There they sign it with their key which allows phones to verify the signature with a public key. Look up pgp encryption. Then they pass it on to metro not for changes but to be made available on their update servers at whatever interval. I know some other lg phones get a kdz bin of updates or stock rom, and they are free to download so that must mean when the carrier gets it they don't t do anything other than distribute.I was thinking that. ZTE signs ota before metro does their thing, correct? In the beginning when we question the missing fastboot, ZTE said metro is the last person to handle updates. So I'm thinking maybe we need tmo/ metro signing keys or there are ways around it.