diff --git a/Debug-with-serial.md b/Debug-with-serial.md
index 44f2fad..344d61b 100644
--- a/Debug-with-serial.md
+++ b/Debug-with-serial.md
@@ -59,4 +59,7 @@ asyncmsg enable
 ``` 
 help
 ``` 
-* MayhemHub currently not support real-time serial command communication. Use others.
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+* MayhemHub currently not support real-time serial command communication. Use others.
+
+# linking error
+It’s possible that the object you are printing isn’t implemented yet (e.g. color obj). If you would like, feel free to implement it by editing usb_serial_asyncsg.cpp and hpp files.
\ No newline at end of file