For the record, the answer was RTFM, sort of. What the FixPak instructions say is to get the "latest ESS device driver" from IBM's Device Driver Pak online. The driver available there is in fact the oldest one I could find anywhere (1.03) -- so I thought I was increasing my chance of success by digging up more recent drivers elsewhere -- however unlike the others, it works.
I just put OS/2 FP15 on my old 760ELD. I had installed IBM's latest driver (v1.04, from the device matrix) before installing the FixPak, and it worked fine. After installing the FixPak, I got TRAPs on boot when the driver loaded. The FixPak readme tells you to get the latest driver if you see this very problem. Fine... I've installed many different flavours of the driver, and all the rev 1.x drivers trap on boot, and the 2.08 driver I found at esstech.com doesn't trap but doesn't load either.
Anyone know what to do here to get sound?
Good day, Peter.