NEC 3550A: now system recognized as CD only



I bought a NEC 3550A DVD burner a couple months ago. First, I installed NEC burner as a “slave drive”, then upgrade the firmware to 1.06. I found out that it took more than 1 hr to burn onto a 4.7Gb disc. On my computer setting, both Primary IDE master channels showing DMA, but one of the slave IDE showing IPO. So I changed IPO to DMA in transfer mode box, but Current transfer mode box grayout and still showing IPO

So next step, I decided to switch NEC DVD burner to master drive. This time my computer recognized NEC DVD burner as a CD drive only. All IDE/ATA controller are showing DMA. What is going on? Do I need to upgrade firmware again? Or this is the burner software problem? Note: I’m using windows XP with sp2. Please advice me how to fix this problem.