diff --git a/How-to-upgrade-4G-extension-firmware.md b/How-to-upgrade-4G-extension-firmware.md
index b15e755..f2fa464 100644
--- a/How-to-upgrade-4G-extension-firmware.md
+++ b/How-to-upgrade-4G-extension-firmware.md
@@ -1,5 +1,9 @@
 # Precautions
-The following-mentioned flashing operation requires your familiarity with Linux and firmware flashing. Please do not attempt it without sufficient experience, as we will not be held responsible for any consequences. Thank you for your understanding.
+The following-mentioned flashing operation requires your familiarity with Linux and firmware flashing. 
+**Please do not attempt it without sufficient experience!**
+**Please do not attempt it without sufficient experience!**
+**Please do not attempt it without sufficient experience!**
+as we will not be held responsible for any consequences. Thank you for your understanding.
 
 once you flashed the new firmware, there is no going back
 even if you switch id from 9011 to 9001 ,mmcli may  not able to see the 4G modem any more.