I've noticed the stability of the firmware on the Zip is quite variable between releases (as though the unstable label wasn't an indication). When I first put it on there I had no end of problems with it, including the entire UI getting frozen when building the library (requiring a hard reset), and my computer recognized the device only one time in four when I plugged it in. I decided to see if they'd updated anything since I initially Rockboxed the Zip, and sure enough there was another version, and so far it's been rock solid. I'm not going to fiddle with it anymore, at least until they finalize the firmware for the Zip, but I was kind of wary of doing anything at all when it was building because that usually resulted in a freeze. I'll definitely have to try your suggestion now that I know it's probably not going to get stuck anymore.
You know you're an audiophile when you'll put up with a buggy release of your favorite portable device firmware just because it's awesome and you won't use anything else.