This is the latest (March 2003)firmware updater (FlashTool V22.214.171.124) for most Philips CDRW, and DVD drives. It covers Win 95 upwards.
It worked fine for me on my PCRW4861K/20, but if you have any reservations, or your computer is likely to crash in the five or so minutes it takes, THEN DON'T DO IT. You will end up with a scrap drive.
Docs are included in the Zip. The models covered by this updater is huge, so read those to see if your drive is covered.