I have changed the logo in seattle.html in SharePoint designer so that it uses SharePoint:SPLinkButton instead of SharePoint:SPSimpleSiteLink and modified it to point to the root site collection. It works on the Site Collection, however when I create subsites the logo still points to the subsite it self. I opened the master page of the subsite I see that it still contains SharePoint:SPSimpleSiteLink not SharePoint:SPLinkButton.
If you cannot use Publishing feature, you need to either update the master page on each Team (sub)site you create or create a Feature that sets the master page of the subsite to be same as at the root site. You can use e.g., feature stapling to automatically run that feature always when subsite is created.