[WP 34S] I finally bricked it :-(

[John Galt]

Hi Josh,

No, I have been unable to resurrect the calculator since the failure. It occurred part way through flashing it, exactly as you described. It's in storage in the event I can ever find someone with a JTAG development system who would like to attempt to fix it, or to definitively diagnose what's wrong.

It is almost certain the damage occurred due to an interruption in power during flashing. There is little or no reason to suspect any problems using a VM, but there is every reason to believe Bernhard's explanation was in fact the cause:

(02-02-2015 09:56 PM)PANAMATIK Wrote:  If programming is not longer possible it can have two reasons, the serial input/output or the whole chip is defective, or the boot loader firmware has overwritten itself or at least the interrupt vector table or the reset vector. This is the most common boot loader software mistake. There is a very short window when the reset vector will be written, about 10 ms, if the transmission is interrupted at that moment, the bootloader cannot start up the next time.

Since that event I have been cautious to use a "very solid" connection to the calculator's serial port. Fabricating that connector has always been the most challenging aspect of this project. If you want to avoid damaging your HP beyond repair, what I wrote earlier is essential:

(02-03-2015 03:30 PM)John Galt Wrote:  ... I'd advise caution to maintain power within limits during flashing.