Okay, it worked. Hm.

Before I FAQ this as I promised, I'll need to run all those SMART tests on the player to be sure the hard disk is in working order.

Incidentally, what indicated a disk problem to me was Hijack telling me "HDA: LOST INTERRUPT" each time I selected a down-down-down shuffle, and subsequent not-remembering-that-playlist-across-reboots. Selecting a smaller playlist would sometimes work without giving me the error and would be fine across reboots. I determined: Bad sector somewhere in the dynamic data partition. Not cable/header trouble because it had no problem reading the song files and playing them back. I reseated the cable, double checked its crimping, double checked the header, and switched the connector anyway to be sure, but no change.

But since it let me zero-out HDA3 without giving me any errors (either on the screen or in the console) and the player seems (cross fingers) to be working perfectly now, then should I assume that the disk is really fine at the hardware level and there was something ELSE wrong I'm not understanding?

Would something like a power failure or a software glitch that causes a reboot, during a dynamic-data-write, cause this kind of error?