Fix issue #456

IMG/cpio/ventoy/hook/debian/ventoy_env2debconf.sh

+#!/bin/sh
+#************************************************************************************
+# Copyright (c) 2020, longpanda <admin@ventoy.net>
+# 
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 3 of the
+# License, or (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <http://www.gnu.org/licenses/>.
+# 
+#************************************************************************************
+
+PATH=$PATH:/ventoy/busybox
+
+set > /ventoy/tmpenvset
+
+for i in $(cat /proc/cmdline); do
+    if echo $i | grep -q "="; then
+        vtKey=${i%=*}
+        if ! grep -q "^$vtKey" /ventoy/tmpenvset; then
+            echo $i >> /ventoy/envset
+        fi
+    fi
+done
+
+cat /ventoy/tmpenvset >> /ventoy/envset