diff --git a/adoptopenjdk.sh b/adoptopenjdk.sh
index 1c6b99f..fb5e39a 100755
--- a/adoptopenjdk.sh
+++ b/adoptopenjdk.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-# requires: curl, sha256sum, awk
+# requires: curl, sha256sum, awk, jq
 set -e
 
 BASE_PATH="${TUNASYNC_WORKING_DIR}"
@@ -7,6 +7,7 @@ BASE_PATH="${TUNASYNC_WORKING_DIR}"
 # 参数为版本，比如8,11等
 function downloadRelease() {
   remote_filelist="$BASE_PATH/$1/filelist"
+  mkdir -p "$BASE_PATH/$1"
   echo -n "" >$remote_filelist
   curl -s "https://api.adoptopenjdk.net/v2/latestAssets/releases/openjdk$1" | \
     jq -r '.[]| [.version,.binary_type,.architecture,.os,.binary_name,.binary_link,.checksum_link,.installer_name,.installer_link,.installer_checksum_link]| @tsv' | \
@@ -20,12 +21,14 @@ function downloadRelease() {
         echo "Skiping $binary_name"
         downloaded=true
       fi
-      while [[ $downloaded != true ]]; do
+      local retry=0
+      while [[ $retry -lt 3 && $downloaded != true ]]; do
         echo "Downloading ${dest_filename}"
         link="$binary_link"
         download_and_check && {
-	        downloaded=true
+            downloaded=true
         }
+        ((retry+=1))
       done
       if [[ ! -z "$installer_name" ]]; then
         dest_filename="$BASE_PATH/$version/$binary_type/$architecture/$os/$installer_name"
@@ -36,13 +39,15 @@ function downloadRelease() {
           echo "Skiping $installer_name"
           downloaded=true
         fi
-        while [[ $downloaded != true ]]; do
+        retry=0
+        while [[ $retry -lt 3 && $downloaded != true ]]; do
           echo "Downloading ${dest_filename}"
           link="$installer_link"
           checksum_link="$installer_checksum_link"
           download_and_check && {
             downloaded=true
           }
+          ((retry+=1))
         done
       fi
     done
@@ -51,12 +56,13 @@ function downloadRelease() {
 function clean_old_releases() {
   declare version=$1
   declare remote_filelist="$BASE_PATH/$version/filelist"
-	declare local_filelist="/tmp/filelist.local"
-	find "$BASE_PATH/$version" -type f > ${local_filelist}
-	comm <(sort $remote_filelist) <(sort $local_filelist) -13 | while read file; do
-		echo "deleting ${file}"
-		rm "${file}"
-	done
+  declare local_filelist="/tmp/filelist.local"
+  [[ ! -f "$remote_filelist" ]] && return 0
+  find "$BASE_PATH/$version" -type f > ${local_filelist}
+  comm <(sort $remote_filelist) <(sort $local_filelist) -13 | while read file; do
+      echo "deleting ${file}"
+      # rm "${file}"
+  done
 }
 
 function download_and_check() {
@@ -67,7 +73,11 @@ function download_and_check() {
     "$link"
   curl -s -S --fail -L ${CURL_OPTIONS:-}  \
     -o "${dest_filename}.sha256.txt.tmp" \
-    "$checksum_link"
+    "$checksum_link" || {
+    echo "Warning: ${dest_filename}.sha256.txt not exist, skipping SHA256 check"
+    mv "${dest_filename}.tmp" "${dest_filename}"
+    return 0
+  }
   sha256sum_check && {
     mv "${dest_filename}.sha256.txt.tmp" "${dest_filename}.sha256.txt"
     mv "${dest_filename}.tmp" "${dest_filename}"
@@ -78,7 +88,7 @@ function download_and_check() {
 function sha256sum_check() {
   expected=$(cat "${dest_filename}.sha256.txt.tmp" | awk '{print $1}')
   actual=$(sha256sum "${dest_filename}.tmp" | awk '{print $1}')
-  if [ "$expected" = "$actual" ]; then
+  if [[ "$expected" = "$actual" ]]; then
     return 0
   else
     return 1