The backdoor is a setuid-binary that gives a root shell when prompted with the correct "password." Deleting the binary removes the backdoor.

A discovered backdoor is a vulnerability. You fix the vulnerability.

I understand that, but I meant it more in a philosophical way. The backdoor is not a bug (it's hard for me to imagine that the backdoor was included by accident), so you can't fix it. You can only remove it.

Also, it's not a vulnerability either (from ZTE's point of view). It's a feature.

You make it more stealth.