From the post How to change WordPress User Role capabilities we know already how to make it for the ordinal not multi-user (MU) WordPress. It this post I will show you how to change the user role capabilities for the WordPress MU platform.
As you know WPMU lets to have multiple blogs under single WordPress installation. Blog list is stored in the wp_blogs database table. We will use blog ID attribute (blog_id field value) from this table. WPMU stores every blog data in the separate database tables set. Every blog data set differs with its blog ID in the name of the database tables, e.g. blog with ID=1 has wp_1_options table, blog with ID=2 has wp_2_options table, etc. So, to get the blog id=1 user roles capabilities from the database we can use this SQL query