Hello folks i've upgraded my open firmware to ver. 4.2.9f1, the whole operation went smoothly, no errors. Some days after it, i've try to use the dvdrom, and i didnt saw any dvd rom in system profiler of OS X 10.3.4. I went to OS 9 and there she was, working properly. After some mourning, i wanted to reinstall OS X but I COULDN'T boot. I've reset PMU,NVRAM,PRAM, yet nothing worked. After some more work i decided to bring it to Apple repair store, there they told me i have corupted filesystem and that might be the source of the problem. So now i wonder, whether there is some version of firmware, without the already installed firmware check, which would let itself apply even on the same firmware. Btw i wonder how could happen a corupted firmware got loaded, doesn't it have some crc checking etc... ? However i'll be glad for any help.