WP 34S will not turn on

[BarryMead]

You had asked a question about the WP-34S (HP-30B) boot loader. The boot loader on this device is not located in a "PROTECTED" area of flash memory as it is with many other flash programmable devices. Unfortunately the boot loader is merely a section of the normal flash memory. Each time you "PROGRAM" the flash memory of the HP-30B (WP-34S), you are overwriting the boot loader as well as the rest of the flash memory that define the behavior of the calculator. This is why "EACH ATTEMPT" to update the firmware has a risk of bricking the device, and why it is so critical that the battery be new, and the cables be wiggle free and solid. If you attempt to program the flash memory and the process is interrupted, you will end up with a bricked calculator. So the only thing special about the JTAG method of programming flash memory is that it can be achieved even without the cooperation of boot loader firmware which reads the serial port interface. On the Swiss Micros DM-15L the boot loader is in a special "PROTECTED" area of memory that cannot be erased using the USB serial interface, so one cannot brick the calculator by a failed attempt to program flash memory as you can with the WP-34S. This is all a moot point if your calculator has a high-current lockup hardware problem, as even a JTAG programmer will probably not be able to fix the issue. It is also worth noting that using such a programmer requires a considerable learning curve and skill level that may not be easy for most users of the Calculator. I happen to be a digital electronics engineer and software developer, who uses these kind of programming devices every day (for Atmel processors not arm processors), so I may have made it seem easier than it really is to use such equipment. For that I apologize. I attempted to be helpful, but I do not want to create financial or technical hardships for others.