Sent for the free OS ROM Upgrade in Sept98; no problem removing old or installing new.HOWEVER Kawai will not tell you anything about what is enhanced or anything; I suspect it was done to clear up spot problems on an unknown range of machines.Possibly the filter envelopes work better; I noticed no other changes.If anyone out there has been through this process and has any insight as to what it was about,let us know! Thanks.

OS upgrade?? Free??
Whats going on here.. How come I don't know about this? Could you possibly pass on the details on where/how I could get it?
I just pulled the old k4 out off the closet. Forgot how cool and grungy it sounded

OS ROM Version 1.4 is available to K4 and K4r users by contacting Tech Support at Kawai US.(800) 421 2177 or (310) 631 1771. You must provide the serial# of your inst. and the current version which is displayed if you hold MASTER while powering up.The new ROM is free provided you return the old one in reusable condition and insure it. They will give you NO INFO but as I recall it is the only chip of that size on the board.Just pay attention to its orientation and use a good insertion/extraction kit. Let me know how it goes.

I'm curious as to how Joopitar8 or anyone else here might have fared trying the K4/K4r upgrade,if you did go ahead with it. I thought the company was great on customer relations and timeliness; in my particular case, though, I didn't notice a dramatic change in the module's operation...maybe less attack transient on the filters at high level, that's about it. Weigh in with your experiences,please!