Success! The drive is running normally again on its original zl1u firmware.
Compiling with Visual Studio 2008 did indeed restore Win2k compatibility.
Using NECWinFlash, I flashed the drive with the ihas424y_zl1w_orig.bin found on your site. The drive ceased blinking, and upon rebooting, my software recognized the drive and its firmware properly.
However, if I push the eject button or order ejection through software, the drive lights up, makes a coughing sound, and does not open. Touching the tray, I could feel that it budges very slightly.
ZL1V, same result.
When I restored ZL1U, the firmware I had originally, everything works just fine, as if nothing had changed. The drive opens and reads entirely per normal. Thank you.
I'm extremely impressed by the rapid response from Liggy, one of the developers. I had a brick, and now I have useful hardware again. I appreciate your work very much.
I don't know what's going on with the higher firmwares, and if you do, I'm happy to hear it, but as far as I'm concerned, the problem is solved. The old firmware works well enough. Thanks again!