First, the old Yahoo finance iChart download is gone for good. In one of the forum posts, a Yahoo employee has confirmed that the free EOD data has been terminated, and will not be reintroduced. Check out this thread and look for reply from Nixon. Yahoo is recently acquired by Verizon, and it must be the new direction.
However, if you check the Yahoo financial page, the CSV download link works, though differently now. It is through a new API that uses an authentication token “crumb” that is linked to a cookie when you access the page.
So there is a work-around to get the same CSV download as before through this new API. I have put together some quick Python3 code. Please check out GitHub for source code yahoo_quote_download.