See the Arduino issue for details and code changes https://github.com/arduino/Arduino/issues/4029 ## <bountysource-plugin> Want to back this issue? **[Post a bounty on it!](https://www.bountysource.com/issues/28169596-fix-flush-implementations-to-match-corrected-code-in-latest-arduino-libraries?utm_campaign=plugin&utm_content=tracker%2F14245935&utm_medium=issues&utm_source=github)** We accept bounties via [Bountysource](https://www.bountysource.com/?utm_campaign=plugin&utm_content=tracker%2F14245935&utm_medium=issues&utm_source=github). </bountysource-plugin>