ASUS has updated firmware for both the ASUS CRW 5232 as well as their CD reader CD-S520.
The new firmware for CRW 5232 is 1.01 and can be found at http://www.asus.com.tw/pub/ASUS/cdrw/5232AS/CRW5232AS_101.zip This is for IDE version only and not the USB.
The firmware 1.13 for CD-S520 can be found at http://www.asus.com.tw/pub/ASUS/cdrom/520A4V13.zip
Makes two great products even better. Would welcome fellow ASUS owners reactions to these firmware.