diff --git a/poky/meta/recipes-rt/README b/poky/meta/recipes-rt/README
index 7d7558d..0144d68 100644
--- a/poky/meta/recipes-rt/README
+++ b/poky/meta/recipes-rt/README
@@ -10,4 +10,4 @@
 use the line above in the $MACHINE.conf in your BSP layer, and specify the
 following in a linux-yocto-rt bbappend recipe:
 
-COMPATIBLE_MACHINE_$MACHINE = $MACHINE
+COMPATIBLE_MACHINE:$MACHINE = $MACHINE