[WIP] Edit android version/security patch based on boot.img
diff --git a/rw-system.sh b/rw-system.sh
new file mode 100644
index 0000000..42866e8
--- /dev/null
+++ b/rw-system.sh
@@ -0,0 +1,35 @@
+#!/system/bin/sh
+
+set -e
+
+if [ "grep ' /system ' /proc/mounts  |cut -d ' ' -f 1 |wc -l" -ne 1 ];then
+	exit 0
+fi
+
+img="$(find /dev/block -type l |grep by-name |grep /kernel$(getprop ro.boot.slot_suffix) |head -n 1)"
+[ -z "$img" ] && img="$(find /dev/block -type l |grep by-name |grep /boot$(getprop ro.boot.slot_suffix) |head -n 1)"
+
+mount -o remount,rw /system
+resize2fs $(grep ' /system ' /proc/mounts |cut -d ' ' -f 1)
+if [ -n "$img" -a ! -f /system/rewrite-spl-done ];then
+	done=1
+	v="$(getSPL $img android)"
+	if [ "$(getprop ro.build.version.release)" != "$v" ];then\
+		sed -i -E "s/ro.build.version.release=.*/ro.build.version.release=$v/g" /system/build.prop
+		sed -i -E "s/ro.build.version.release=.*/ro.build.version.release=$v/g" /system/etc/prop.default
+		done=''
+	fi
+
+	v="$(getSPL $img spl)"
+	if [ "$(getprop ro.build.version.security_patch)" != "$v)" ];then
+		sed -i -E "s/ro.build.version.security_patch=.*/ro.build.version.security_patch=$v/g" /system/build.prop
+		sed -i -E "s/ro.build.version.security_patch=.*/ro.build.version.security_patch=$v/g" /system/etc/prop.default
+		done=''
+	fi
+	
+	if touch /system/rewrite-spl-done && [ ! "$done" ];then
+		mount -o remount,ro /system
+		reboot
+	fi
+fi
+mount -o remount,ro /system