diff --git a/How-to-use-the-4G-extension.md b/How-to-use-the-4G-extension.md
index 46b84c6..a8c9df6 100644
--- a/How-to-use-the-4G-extension.md
+++ b/How-to-use-the-4G-extension.md
@@ -42,9 +42,10 @@ mmcli -m any | grep "primary port"
 you will get like `cdc-wdm0` or  `ttyUSB2` , if you got `cdc-wdm0`, we suggest blacklisting some kernel modules by
 
 ```
-$ cat /etc/modprobe.d/blacklist-qmi.conf
+sudo bash -c 'cat << EOF > /etc/modprobe.d/blacklist-qmi.conf
 blacklist qmi_wwan
 blacklist cdc_wdm
+EOF'
 ```
 
 `ttyUSB2` is what we want,but **cdc-wdm0** is still worth to try if you know it well