diff --git a/docs/hassio_addon_config.md b/docs/hassio_addon_config.md
index 4fcf4811..be711bef 100644
--- a/docs/hassio_addon_config.md
+++ b/docs/hassio_addon_config.md
@@ -123,6 +123,7 @@ The config for an add-on is stored in `config.json`.
 | environment | dict | no | A dict of environment variable to run add-on.
 | audio | bool | no | Boolean. Mark this add-on to use internal an audio system. The ALSA configuration for this add-on will be mount automatic.
 | gpio | bool | no | Boolean. If this is set to True, `/sys/class/gpio` will map into add-on for access to GPIO interface from kernel. Some library need also `/dev/mem` and `SYS_RAWIO` for read/write access to this device.
+| devicetree | bool | no | Boolean. If this is set to True, `/sys/firmware/devicetree` will map into add-on.
 | stdin | bool | no | Boolean. If that is enable, you can use the STDIN with Hass.io API.
 | legacy | bool | no | Boolean. If the docker image have no hass.io labels, you can enable the legacy mode to use the config data.
 | options | dict | yes | Default options value of the add-on