The iHASx24 Y/Z drives are different hardware from the iHASx24 A drives. (At the very least, the Y uses an NEC chipset; the A, a MediaTek). As such, the firmware is not interchangeable. Trying would kill the drive.
A few people are working on the flashing tools that could be used to get the drive to its original make and model, an Optiarc AD-724xS. See this thread: http://club.cdfreaks.com/f44/liteon-plds-24ay-z-ihas124-224-324-424-y-uses-nec-chipset-300181/
Unless the drive booktypes DL as DVD-ROM right now (I thought the stock Optiarc firmware did this, maybe the LiteOn version does not), you will probably be waiting for a patch to enable booktyping or crossflash to Optiarc firmware.