Here it is the newest patch for the ASUS HD5850. Works with 10.12+ only.
ATIConnectorsController: uakari
<dict> <key>Disabled</key> <false/> <key>Find</key> <data> AAQAAAAEAAAAcQAAAAAAABIEBAEAAAAABAAAABQAAAAA cQAAAAAAAAESAQMAAAAAAAIAABQAAAAAcQAAAAAAAAAA BgUAAAAAAAgAAAACAAAAcQAAAAAAACIFBQQAAAAA </data> <key>Name</key> <string>AMD5000Controller</string> <key>Replace</key> <data> AAgAAAQCAAAAcQAAAAAAABIEBAEAAAAABAAAABQAAAAA cQAAAAAAACIFAQQAAAAAAAQAAAQAAAAAcQAAAAAAABEC BgMAAAAABAAAABQCAAAAcQAAAAAAABAABQUAAAAA </data> </dict>
UPDATE: On 10.12.4+, you must set the color depth to “millions of colors” with SwitchResX, to solve the color bug in the newest legacy driver.