To rebuild the firmware with this patch, run as root:

$ mkdir install
$ tar -xf install.img -C install
$ cd install/package2
$ mkdir etc
$ tar -jxf usr.local.etc.tar.bz2 -C etc
$ cd etc
$ patch -p1 -i ../../../rcS.patch
$ rm ../usr.local.etc.tar.bz2
$ tar -jcf ../usr.local.etc.tar.bz2 *
$ cd ..
$ rm -rf etc
$ cd ..
$ rm ../install.img
$ tar -cf ../install.img *
$ cd ..
$ rm -rf install

--- a/rcS	2013-08-08 23:22:58.000000000 -0700
+++ b/rcS	2013-08-08 23:22:58.000000000 -0700
@@ -63,3 +63,10 @@
 
 echo 2 /tmp/hdd/volumes/HDD1/ > /sys/realtek_boards/misc_operations
 
+# Source init script on USB stick
+(
+	sleep 30  # wait for usb mount
+	if [ -f /tmp/usbmounts/sda/init.sh ]; then
+		source /tmp/usbmounts/sda/init.sh
+	fi
+) &