Teac CD-W540E possibly firmware problem



hi everyone,
I need help. Since I updated the firmware of my writer (Teac CD-W540E v1.0K) I’ve had dma problem. When the ide-cable of writer is in dma mode it is not possible to write without errors. Actually Nero says it wrote CD successfully, but when I check data verification option, I always get an error message. It is weird. CDs are written successfully with full of errors. When I change dma to pio mode, it is ok but this time the writing speed falls incredibly. CD copy lasts 15-20 minutes on the fly (cd drives are on different cables), writing at 40x lasts 6-8 minutes (in dma mode 3-3,5 minutes). I overwrote firmware several times. I don’t know what to do now. I’ve tried all known medias: CMC, Ritek, Gigastorage, Princo… Same result. I use Celeron 1.0 GHz overclocked from 800 MHz. Thanks…