HP30b flashed with WP31 no longer responding

[mfleming]

Hi all,

I successfully flashed a couple of HP30b's with the WP34 bin file in the past. I used a setup similar to that described in the article describing the use of an Arduino Nano. The calculator was powered from the 3.3V supply of a Sparkfun FTDI-based USB to Serial board, with the internal batteries removed. For safety, I had 330 ohm resistors in series with the Tx/Rx pins.

When I tried to do the same with a new HP30b and the WP31 bin file, the calculator was successfully erased and the file downloaded. The download time seemed a bit short at only 4 seconds, but MySamBa seemed to complete without complaint. The calculator would not power on though.

Subsequent attempts to flash the file again or use a WP34 file all failed because MySamBa could not connect to the calculator. I tried the usual steps of removing and reapplying power, restarting MySamBa, connecting Tx/Rx directly without the limit resistors, repeating the erase procedure and so on to no avail. I would think I've done enough to recover from an I/O pin lockup, and I couldn't have raised the Rx/Tx pins above Vcc.

At this point it looks as though the calculator is dead. A few questions for those more experienced; Is there a way to tell if the calculator is truly bricked? Could a corrupt bin file be responsible? Could a JTAG unit bypass the bootloader?

Given how hard it is getting to find a 30b calculator, I'd hate to abandon this guy without some attempt at recovery, assuming it is possible. Suggestions greatly appreciated (including buy one from Eric ).

Thanks,
~ Mark