Mine worked perfect i have a 40gb model with a 750gb wd black now. I have playstation plus so when i turned it on the update was there i applied it and done. if you don't have plus get it now this month had a ton of free games!
Speaking of 4.20 issues on the PS3 my WD external drive was playing ALL HD home movies smoothly. Then I was forced to update this morning and it is choppy as hell and reboots etc. would not resolve this. My older piano finish PS3 also was updated to 4.20 and has no issues running the videos. I don't understand how a software update on two machines can cause such a dramatic difference in how the videos run? Is anyone else having issues with their external drives after the update?
PS3 slim here and it updated fine. Honestly every time there's an update some people seem to have trouble. I've never had an issue and neither has anyone I know.