[WP-34S] Cable and flashing options for Mac users

[BarryMead]

One of the HP-30B calculators that I modified had a "DEFECTIVE" zero ohm jumper on JP5 or JP6
I don't remember which one it was. Use your ohmmeter to see if both sides of these zero ohm jumpers
are connected to each other. I had to tack a small wire across the defective zero ohm jumper and then
I was able to re-flash that calculator. I had symptoms very similar to yours until I fixed the jumper.
The factory may have never actually used the 6-pin programming inputs, because they probably
originally programmed the flash using the JTAG connector.