I'm perhaps a bit of on the target here, but wouldn't it be better to fix it on the other end, the WHDload software? (However, it's not something you can decide, i know that.)
This pretty much means everyone who has a 1230/56 should send the card back to you, as well as everyone who bought a refurbished 1230/28 with a MMU, unless they intend never to use the MMU for WHDloads. OK, so i don't know how much WHDLoads gain from a MMU if at all, or, if there are any WHDLoads thet require the MMU to work.
But somehow i would rather see this "fixed" in software. And it's not only due to me not wanting to spend the 10 euro, and shiping both ways. Again it's a matter of "what if the next owner needs this to work". It's not like Jens is going to want to provide the service of updating the cards for years and years to come.