diff --git a/conf/layer.conf b/conf/layer.conf
index 45fba0d..5d6045e 100644
--- a/conf/layer.conf
+++ b/conf/layer.conf
@@ -6,7 +6,7 @@ BBFILE_PRIORITY_external-toolchain = "1"
 BBFILE_PATTERN_external-toolchain = "^${LAYERDIR}/"
 
 LAYERDEPENDS_external-toolchain = "core"
-LAYERSERIES_COMPAT_external-toolchain = "thud warrior zeus dunfell gatesgarth"
+LAYERSERIES_COMPAT_external-toolchain = "thud warrior zeus dunfell gatesgarth hardknott"
 LAYERDIR_external-toolchain = "${LAYERDIR}"
 
 BBFILES += "${@' '.join('${LAYERDIR}/%s/recipes*/*/*.%s' % (layer, ext) \