*** Version 1.4 UPDATE ***
HobbyRoms came through. I received some Version 1.4 proms!!
* Swapped out the Ver 1.3 prom and the DSP1124P booted up indicating "1.4"
* Configured the DSP1124P MIDI interface according to the REW help
* Built a set of filters in REW
* Downloaded to the DSP1124P program #3, left engine
* Manually read back each filter parameter - looks fine
* Downloaded to the DSP1124P program #3, right engine
* Manually read back each filter parameter - looks fine
Concern: Stability of version 1.4 firmware - Need to check this rigorously. Behringer released ver 1.3 with serious bugs; who says that version 1.4 was checked out so well either? It would be helpful if REW software could read back filter settings. It would be awesome if REW software would read back and *verify* downloaded filter settings. Until that happens, we'll have to manually check a bunch of downloads and look for errors. Only then can we claim 100% success.
Without read-back verification your best bet is to do an audio sweep with the new filters. If they response looks good, then the filters are probably what you downloaded.
For those with sales receipts - good luck getting your prom from Behringer, it may take weeks at best as they indicated they will take a most circuitous route to dealing with each individual's defective product.
For those without sales receipts (and for those with one as well) - you might as well order from HobbyRoms. They are a great service.
At last! Now I can get on with tuning my high-definition sub (which I mounted in a concrete box dug into the bedrock beneath my concrete slab floor). It sounded decent until I put a 1" thick custom plate steel shelving unit 6" above it - this shifted the phase as well as excited a couple room-resonance peaks. Initial tests suggest that the DSP1124P should easily be able to fix this. I just needed MIDI to work so I can set up a bunch of "house curves" for listening comparisons...
-Cheers