Not too many people have a cable to reprogram HP calculators. The HP15 LE cable had the same connector, but it is NOT compatible. You need to make destructuve changes to the old cable to be able to use with the new HP calculators.
Well, we have one, so that we can reprogram these calculators. We are offering that service. Now the important thing is to have a new firmware!
We are testing a couple of possible firmwares that solve the main bug in the HP16c emulation. One of them is working well so far! We'd need to get the permissions, but this one is a strong candidate to replace the original firmware. Too early to decide, though.
We are also considering producing our own cable - industrially. But this will take longer...