diff --git a/cron-callback.sh b/cron-callback.sh
index bc304396e2c2007256e378aa845263012c00cee7..53b3156153205060ba76452b6cce835da34ce9a5 100755
--- a/cron-callback.sh
+++ b/cron-callback.sh
@@ -45,11 +45,11 @@ function download_cloud_img_if_not_exist () {
 
     echo2 "+ Downloading cloudimg $cloudimg..."
     if which aria2c; then
-        aria2c -o "base/$cloudimg" "${knowledge[$cloudimg]}" || ! echo2 "Failed to download ubuntu cloudimg" || return $?
+        aria2c  -o "base/$cloudimg" "${knowledge[$cloudimg]}" || ! echo2 "Failed to download ubuntu cloudimg" || return $?
     elif which wget; then
-        wget   -O "base/$cloudimg" "${knowledge[$cloudimg]}" || ! echo2 "Failed to download ubuntu cloudimg" || return $?
+        wget    -O "base/$cloudimg" "${knowledge[$cloudimg]}" || ! echo2 "Failed to download ubuntu cloudimg" || return $?
     elif which curl; then
-        curl   -o "base/$cloudimg" "${knowledge[$cloudimg]}" || ! echo2 "Failed to download ubuntu cloudimg" || return $?
+        curl -L -o "base/$cloudimg" "${knowledge[$cloudimg]}" || ! echo2 "Failed to download ubuntu cloudimg" || return $?
     fi
 }