diff --git a/README.md b/README.md
index 23bb14f..bca9909 100644
--- a/README.md
+++ b/README.md
@@ -51,8 +51,8 @@ sudo sh -c "$(wget -O - https://github.com/brentybh/debian-netboot/raw/master/ne
 
 If `-c CN` is used, Chinese Special options will be setup for good connectivity and experience against GFW.
 
- - Default archive mirror is `http://ftp.cn.debian.org/debian`.
- - Default security mirror is `http://ftp.cn.debian.org/debian-security`.
+ - Default archive mirror is `https://mirrors.ustc.edu.cn/debian`.
+ - Default security mirror is `https://mirrors.ustc.edu.cn/debian-security`.
  - Default time zone is `Asia/Shanghai`.
  - Default NTP server is `cn.ntp.org.cn`.
  - Default DNS is `156.154.70.5 156.154.71.5`.
diff --git a/netboot.sh b/netboot.sh
index 732237b..492cf84 100644
--- a/netboot.sh
+++ b/netboot.sh
@@ -101,8 +101,8 @@ done
 
 case "$COUNTRY" in
   CN)
-    PROTO=${PROTO:-http}
-    HOST=${HOST:-ftp.cn.debian.org}
+    PROTO=${PROTO:-https}
+    HOST=${HOST:-mirrors.ustc.edu.cn}
     TIME_ZONE=${TIME_ZONE:-Asia/Shanghai}
     NTP=${NTP:-cn.ntp.org.cn}
     SECURITY=${SECURITY:-true}