I have read and tried the advice, to add the block to front-page, make it visible sitewide, and then configure a block inside a course for appearace inside courses. So far so good.
No I have a new block that can only be added to a course, because it only makes sense within a course. I want it on every course though, without editing hundreds of courserooms manually. The aforementioned method only works for blocks that can be added to the front page, how do I achieve the same thing for blocks restricted to courses?