Sorry to be the second guy to drag this thread back up, but if any kind soul who owns that coveted "plus" version of the SDR 1000 ever feels like reading the contents of that firmware EPROM, I'm sure I wouldn't be the only one to be in your debt. I put a support query in to Ibanez a few days ago, but that unit's old enough now that I'm not really getting my hopes up. Another post I saw suggested some sort of upgrade kit used to go out for the original SDR's. I'm guessing it was mainly the chip (originals use a D27C256-25). I'm not sure if the Sony version (MU-R201) is 100% compatible or not, as it seems to have a slight difference in the front panel memory buttons. Be warned- the chip may not be socketed, but the bottom of the PCB is fairly easy to access without full disassembly.
The upgrade supposedly adds new reverb algorithms (equivalent to the Sony?), but also adds function to the rear panel remote jack, which I had considered playing with. The original's remote implementation is for simple patch changes. A full featured, display-equipped remote showed up later, but appears to need that newer firmware.
Much Thanks!
PS- As with the previous poster, my SDR had an intermittent supply rail. In my case, the supply to the display would drop out or fail to start. It seems to have been that main 9-pin connection from the transformer, but in addition to cleaning it, I reflowed some joints in that area just in case. Solid as a rock now.