Another option is to use the JP1 software without the cable. Make your own .wav file for the upgrade you need and load it from your PC's speaker rather than your phone.

I don't know that you'll get any different result from the PC's speaker than from the phone, but I think it's worth trying. It also is easier to retry, since there isn't a second person involved.

Are you confident you followed the instructions to get your 8910 ready to receive the signal right before it was sent (not so soon that it gives up nor so late that it missed the beginning)?

What setup code(s) were they trying to send? What device(s) are they for? To make your own upgrade without decoding any learned signals you need some other source for the information. Probably someone here already has that information and can identify it either by setup code number or by device type, brand, and model.