Silent authentication in a Device Flow

Hi All!
I am authenticated with my mobile app. I want to authenticate my webapp through device Flow.
The problem here is that I am not able to reuse the session in the mobile app. Each time I access the verification_uri_complete, the browser flows asks for username and password, and obviously I want to avoid it.

After confirming the code, there is a request to /device/confirmation?state=xxxxx and the response is a redirect to /authorize/resume?state=xxxxx. I tried intercepting this request and adding “prompt=none” but it keeps asking for username and password.

How can I achieve this flow?