Because this is nigh impossible to find in 2017, I thought I'd share it with teh Internetz. There's speculation that Roland pulled it because they discovered something about it doesn't work correctly, but I have no idea. Still, it would seem prudent not to do the update unless it's truly necessary.
If anyone has a version v1.03 rollback procedure then it would be risk-free, but I don't think that's going to materialize. So, use this at your own risk--you'll be stuck with it once it's done.
Roland JP-8080 v1.04 flash memory update for operating system (SysEx MIDI):
Roland JP-8080 (JP8080) OS Firmware Update
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