diff --git a/README-zh.md b/README-zh.md
index b7aa4b2..96a21e6 100644
--- a/README-zh.md
+++ b/README-zh.md
@@ -16,9 +16,7 @@ macOS 的 DPI 机制和 Windows 下不一样，比如 1080p 的屏幕在 Windows
 
 ![设置](./img/preferences.jpg)
 
-<video width="100%" controls autoplay loop>
-  <source src="./img/hidpi.mp4" type="video/mp4">
-</video>
+![设置](./img/hidpi.gif)
 
 ## 使用方法
 
diff --git a/README.md b/README.md
index b4777f6..ea4b938 100755
--- a/README.md
+++ b/README.md
@@ -14,9 +14,7 @@ System Preferences
 
 ![Preferences](./img/preferences.jpg)
 
-<video width="100%" controls autoplay loop>
-  <source src="./img/hidpi.mp4" type="video/mp4">
-</video>
+![Preferences](./img/hidpi.gif)
 
 ## Usage
 
diff --git a/hidpi-zh.sh b/hidpi-zh.sh
index a60665c..c816119 100755
--- a/hidpi-zh.sh
+++ b/hidpi-zh.sh
@@ -99,9 +99,6 @@ EEF
     #
     get_edid
     
-    edID=$(echo $EDID | sed 's/../b5/21')
-    EDid=$(printf $edID | xxd -r -p | base64)
-
     thisDir=$(dirname $0)
     thatDir="/System/Library/Displays/Contents/Resources/Overrides"
     Overrides="\/System\/Library\/Displays\/Contents\/Resources\/Overrides\/"
@@ -438,6 +435,14 @@ function enable_hidpi_with_patch()
 {
     choose_icon
     main
+
+    version=${EDID:38:2}
+    basicparams=${EDID:40:2}
+    checksum=${EDID:254:2}
+    newchecksum=$(printf '%x' $((0x$checksum + 0x$version +0x$basicparams - 0x04 - 0x90)) | tail -c 2)
+    newedid=${EDID:0:38}0490${EDID:42:212}${newchecksum}
+    EDid=$(printf $newedid | xxd -r -p | base64)
+
     /usr/bin/sed -i "" "s:EDid:${EDid}:g" $dpiFile
     end
 }
diff --git a/hidpi.sh b/hidpi.sh
index 85c86e6..5f11596 100755
--- a/hidpi.sh
+++ b/hidpi.sh
@@ -98,9 +98,6 @@ cat << EEF
 EEF
     #
     get_edid
-    
-    edID=$(echo $EDID | sed 's/../b5/21')
-    EDid=$(echo $edID | xxd -r -p | base64)
 
     thisDir=$(dirname $0)
     thatDir="/System/Library/Displays/Contents/Resources/Overrides"
@@ -438,6 +435,14 @@ function enable_hidpi_with_patch()
 {
     choose_icon
     main
+
+    version=${EDID:38:2}
+    basicparams=${EDID:40:2}
+    checksum=${EDID:254:2}
+    newchecksum=$(printf '%x' $((0x$checksum + 0x$version +0x$basicparams - 0x04 - 0x90)) | tail -c 2)
+    newedid=${EDID:0:38}0490${EDID:42:212}${newchecksum}
+    EDid=$(printf $newedid | xxd -r -p | base64)
+
     /usr/bin/sed -i "" "s:EDid:${EDid}:g" $dpiFile
     end
 }
diff --git a/img/hidpi.gif b/img/hidpi.gif
new file mode 100644
index 0000000..457bed0
Binary files /dev/null and b/img/hidpi.gif differ
diff --git a/img/hidpi.mp4 b/img/hidpi.mp4
deleted file mode 100644
index 284c62b..0000000
Binary files a/img/hidpi.mp4 and /dev/null differ