>>101178724
They are violating the HTTP standard. This is an issue on their server.
HEAD requests are supposed to return the same Status Code as if you made a GET request.
$ curl -s -o /dev/null -X GET --write-out '%{http_code}' "http://cdns.jp-primehome.com:8000/zhongying/live/playlist.m3u8?cid=gd01"
200
$ curl -s -o /dev/null -X HEAD --write-out '%{http_code}' "http://cdns.jp-primehome.com:8000/zhongying/live/playlist.m3u8?cid=gd01"
404
The only way to detect this would be to issue a real GET request and seeing if you get back a response greater than zero bytes. Having to download the entire file is a bit wasteful though.