From 6568972abca37e33e031e1f2651a68a86491082b Mon Sep 17 00:00:00 2001
From: longpanda <support@iventoy.com>
Date: Thu, 6 Aug 2026 12:51:19 +0800
Subject: [PATCH] Fix Persistence intermittently fails on Ubuntu 24.04 (#3718)

---
 .../ventoy/hook/debian/casper-perst-wa.sh     | 19 +++++++++++++++++++
 IMG/cpio/ventoy/hook/debian/default-hook.sh   | 13 +++++++++++++
 IMG/cpio/ventoy/hook/ventoy-hook-lib.sh       |  3 +++
 3 files changed, 35 insertions(+)
 create mode 100644 IMG/cpio/ventoy/hook/debian/casper-perst-wa.sh

diff --git a/IMG/cpio/ventoy/hook/debian/casper-perst-wa.sh b/IMG/cpio/ventoy/hook/debian/casper-perst-wa.sh
new file mode 100644
index 00000000..9da3bf70
--- /dev/null
+++ b/IMG/cpio/ventoy/hook/debian/casper-perst-wa.sh
@@ -0,0 +1,19 @@
+
+find_cow_device() {
+    tgt_pers_label="${1}"
+    vt_pers_label=""
+    vt_pers_dev=""
+    
+    if [ -f /ventoy/ventoy_persistent_label -a -f /ventoy/ventoy_persistent_dev ]; then
+        vt_pers_label=$(cat /ventoy/ventoy_persistent_label)
+        vt_pers_dev=$(cat /ventoy/ventoy_persistent_dev)        
+    fi
+
+    if [ "$tgt_pers_label" = "$vt_pers_label" ]; then
+        echo "$vt_pers_dev"
+    else
+        find_cow_device_back "$@"
+    fi    
+}
+
+find_cow_device_back() {
diff --git a/IMG/cpio/ventoy/hook/debian/default-hook.sh b/IMG/cpio/ventoy/hook/debian/default-hook.sh
index 5db56e35..bc61e107 100644
--- a/IMG/cpio/ventoy/hook/debian/default-hook.sh
+++ b/IMG/cpio/ventoy/hook/debian/default-hook.sh
@@ -31,6 +31,19 @@ if [ -e /init ] && $GREP -q '^mountroot$' /init; then
             $SED "s#^  *LIVEMEDIA=.*#LIVEMEDIA=/dev/mapper/ventoy#" -i /scripts/casper
         fi
     fi
+    
+    #workaround for issue #3718
+    if [ -f $VTOY_PATH/ventoy_persistent_map -a -f /scripts/casper-helpers ]; then
+        echo 'fix casper cow udev issue' >> $VTLOG
+        if $GREP -q '^find_cow_device\(\).*{' /scripts/casper-helpers; then
+            VTINS_LINE=$($GREP -n '^find_cow_device\(\).*{' /scripts/casper-helpers | $AWK -F':' '{print $1}')
+            $AWK "NR < $VTINS_LINE"  /scripts/casper-helpers  >  /ventoy/casper-helpers-tmp
+            $CAT $VTOY_PATH/hook/debian/casper-perst-wa.sh    >> /ventoy/casper-helpers-tmp
+            $AWK "NR > $VTINS_LINE" /scripts/casper-helpers   >> /ventoy/casper-helpers-tmp
+            $CAT /ventoy/casper-helpers-tmp > /scripts/casper-helpers
+        fi
+    fi
+    
 elif [ -e "$CD_DETECT" ]; then
     echo "$CD_DETECT exist, now add hook in it..." >> $VTLOG
     $SED  "1 a $BUSYBOX_PATH/sh $VTOY_PATH/hook/debian/disk_mount_hook.sh"  -i "$CD_DETECT"
diff --git a/IMG/cpio/ventoy/hook/ventoy-hook-lib.sh b/IMG/cpio/ventoy/hook/ventoy-hook-lib.sh
index 2b413a47..4d62264d 100644
--- a/IMG/cpio/ventoy/hook/ventoy-hook-lib.sh
+++ b/IMG/cpio/ventoy/hook/ventoy-hook-lib.sh
@@ -512,6 +512,9 @@ ventoy_create_persistent_link() {
         VTLABEL=casper-rw
     fi
 
+    echo "$VTLABEL" > $VTOY_PATH/ventoy_persistent_label
+    echo "/dev/$vtDM" > $VTOY_PATH/ventoy_persistent_dev
+
     vtlog "Persistent Label: ##${VTLABEL}##"
 
     if ! [ -e /dev/disk/by-label/$VTLABEL ]; then