Changing default jupyterhub favicon

In all jupyterhub templates I am able to change fav-icon by over writing
{% block favicon %}
{% endblock %}
but still in tree page Iam getting default favicon of jupyterhub how should I change this?

The favicon on /tree and /lab endpoints coming from notebook and JupyterLab. You will have to override them on notebook/JupyterLab. If I am not wrong, there is no easy way to configure favicon for JupyterLab and notebook. You will have to write a custom extension that changes it. Look at this thread for an idea on how the extension looks like.