diff --git a/Devterm-CM3-rpi-os-image.md b/Devterm-CM3-rpi-os-image.md
index 4281469..0ff988d 100644
--- a/Devterm-CM3-rpi-os-image.md
+++ b/Devterm-CM3-rpi-os-image.md
@@ -67,7 +67,7 @@ Modify the `desktop_bg` color to `#202020`
 
 #### config.txt
 
-Add dtparam=audio=on to solve the problem of no sound card under HDMI
+Add `dtparam=audio=on` to solve the problem of no sound card under HDMI
 
 ##### /etc/hostname to clockworkpi