Another stupid flashing cable question HP-30b / HP-15C CE

[AnnoyedOne]

(09-27-2024 02:09 PM)Eric Rechlin Wrote:  Since it completed the transfer...

I've never used MySAMBA so it may look for handshake responses. Or not. It should.

(09-27-2024 02:09 PM)Eric Rechlin Wrote:  I believe you need to hit Reset after flashing in order to start the calculator.

FYI I think my HP-15C CE did too but I could be wrong.

As for different firmware versions I have no idea.

A1

[Maximilian Hohmann]

Hello!

(09-27-2024 01:21 PM)AnnoyedOne Wrote:  It would seem that is working but the download doesn't even though Samba thinks it does. I'd double check your connections (RXD/TXD reversed at one/both ends?).

As it can't get worse, I swapped the TX/RX cables and tried again. Nothing happendend, MySamba reported "No connection" as expected.

(09-27-2024 01:21 PM)AnnoyedOne Wrote:  The HP-15C CE firmware isn't protected (but could be) so the ERASE button just starts the bootloader. Reflashing and VoyagerSave work in XP/Win7 virtual machines (VM's) for me.

Flashing of the HP-15C CE was no problem at all. In my setup it worked only with Windows 10, but my only Windows alternative was XP.

(09-27-2024 02:09 PM)Eric Rechlin Wrote:  Since it completed the transfer, that tells me the cable is working fine. I can see a couple potential problems. The most common is that with the 20b/30b (unlike the 15c CE), I believe you need to hit Reset after flashing in order to start the calculator. Though with several battery changes since, you've probably already essentially done that.

I must have tried it 50 times by now with every possible sequence of Erase-Reset-On. It never worked as expected.

(09-27-2024 02:09 PM)Eric Rechlin Wrote:  The next most common is that you may have installed a version of the firmware not compatible with your calculator as currently configured. Specifically I mean installing a crystal version of the firmware without the crystal working. To test this, try installing the non-crystal version (you didn't specify which version you installed, so I assume it's the crystal version). If that fixes it, then double-check your crystal/caps and how you soldered them, make any necessary corrections, and then try flashing the crystal version again.

As I already had installed the crystal I tried to flash it with the "calc_xtal.bin" file. The result was as described above.
Today I took another new untouched HP-20b and attempted to flash it with the WP-31s software (my thought: less bytes, less chances for errors). Everything went as by the manual, but again, I only got the "Erased" display as before and no funcions at all.

The only thing left to try is to connect the Vcc line (jumpered to 3.3V) from the USB-serial adapter to the calculator and leave out the batteries completely. Maybe the common supply voltage will do some benefit?

Regards
Max

[HPing]

I don't know if these slightly different instructions will help or brick the calculator
https://web.archive.org/web/202009182049...uick_start

https://commerce.hpcalc.org/34showto.php

[AnnoyedOne]

Quote:As it can't get worse, I swapped the TX/RX cables and tried again. Nothing happended, MySamba reported "No connection" as expected.

Well that proves that the bootloader/MySamba uses handshaking at least. And that your cable is good. Take your "wins" where you can!

Quote:...but my only Windows alternative was XP.

That'd work but you have to load the Atmel USB-serial driver included with SAM-BA 2.16 (I've done it). Win7+ has that built-in and it is automatically installed.

Quote:It never worked as expected.

José Divasson says that he's "bricked" multiple HP-15C LE's (Atmel AT91SAM7L128 based calculators).

Since the calculator displays "Erased" I assume that it has a custom bootloader.

I have no suggestions left. However I have a theory. That could take a while to post.

A1

[AnnoyedOne]

Here's my theory. It is just a theory based on my experience. I don't own any AT91SAM7L128 based calculators, cables, software. Nothing.

To start with I have to explain my own experience with flash upgradable firmware. This is unrelated to HP calculators. And it may be long.

Over a decade ago I developed (hardware/firmware/software) for a product. I used an ARM based SoC part for it. Similar to the ones used in HP calculators but not the same. The product had a two line alphanumeric display, for messages, a few buttons but no keyboard.

As part of the project I wrote a totally custom bootloader that allowed the main application to be updated in the field. The SoC part I used did not have one built-in although the manufacturer may've had an off-the-shelf one (with source code). I don't remember.

That bootloader performed two checksum (32-bit CRC's--the SoC had a hardware generator) checks before starting the main application.

Every "application" had a "header". It had one checksum. The actual code had another. If one or both were invalid the bootloader would not start the application and the product was "dead" (aka "bricked"). Over time I changed the header which meant a new bootloader/application. A pair. That was fine because I had control of both parts (source code, tools, etc).

However there was problem. The product was already in production and old bootloaders were in the field. Because the application header had changed an updated application would not be recognised. So I wrote an "application" that flashed the new bootloader. Updating this older design was a two step process.

Load the bootloader update (reflash) application
Load the new application

Because the display showed the bootloader version/date on the display this was fine.

To my theory. HP may've done something similar. With a custom bootloader all bets are off. It may've also changed over time. Any firmware update may've required a new bootloader as well as an application. If so that probably wasn't known outside of HP. Any 3rd party developer may not even know about it.

Again all this is a theory only. But it matches what I've read. Good cable, software, reflashing but still no-go.

The solution would be

Finding an application image that matches the bootloader. That may be very hard/impossible.
Update the bootloader to one that that matches the application. Less hard but risky. If reflashing fails the product is totally dead.

As an aside this is the issue with 3rd party updates. They know only what they know. The manufacturer knows everything.

A1

PS: I once performed a firmware update (beta) on a consumer product I'd bought. It failed and was "bricked". I sent it to the manufacturer for repair. No issues after that. However with HP and these "old" calculators that can't be done. HP may not even know how to fix them.

PPS: The HP-15C CE and 2015+ HP-12C+ use a different SoC and contain a generic bootloader from the manufacturer. None of the above applies to them.

[Maximilian Hohmann]

Hello,

thanks for your detailed explanations, these may come handy one day...
I have since many years been tinkering with Arduinos and similar microcontroller boards, most of which use Atmel chips. The USB programming adapters usually also contain chips from FTDI (or clones thereof). My - so far: failed - attempts at flashing the Atmel based HP-20b calculators are a new experience. But I am certain that a solution will be found.

(09-29-2024 11:54 AM)AnnoyedOne Wrote:  José Divasson says that he's "bricked" multiple HP-15C LE's (Atmel AT91SAM7L128 based calculators).

I would never attempt to flash an HP-15C LE. They are much too rare and precious to risk anything (asking prices these days are typically over 200$/Euro) and why would one want to flash their system in the first place.

One of the two (ex?) employees of the calculator division from HP, who used to be very active on this forum (C. de Brébisson and T. Wessman), once wrote that calculators like the HP-20b and HP-30b cannot be bricked by flashing attempts. The bootloader is hardwired. So there is always hope.

Regards
Max

[AnnoyedOne]

(09-30-2024 10:59 AM)Maximilian Hohmann Wrote:  ...why would one want to flash their system in the first place.

I think that he was trying to reflash firmware for customers. Didn't the LE have a firmware update or two? Perhaps he'll explain more.

https://www.hpmuseum.org/forum/thread-22...#pid190941

(09-30-2024 10:59 AM)Maximilian Hohmann Wrote:  So there is always hope.

Yes. The bootloader is working. Your cable is working. MySamba is working. You just need a known good image to match! Perhaps the WP34S developers have ones.

A1

[AnnoyedOne]

(09-30-2024 10:59 AM)Maximilian Hohmann Wrote:  ...wrote that calculators like the HP-20b and HP-30b cannot be bricked by flashing attempts.

Technically correct. "Bricked" means totally non-functional. Your 20B's are "non-functional" as calculators but as you say the bootloader is working.

BTW I did "brick" the product mentioned above a few times. Since I had a JTAG programmer etc I simply reflashed the SoC. Few of us have one or have access so a non-functional bootloader = "bricked".

A1

[AnnoyedOne]

No consolation but you're not the only one.

http://www.hpmuseum.org/forum/thread-2985.html

A1

[AnnoyedOne]

Max,

I haven't given up--yet

The HP-20B "development kit"

https://www.hpcalc.org/other/pc/hp20b_de...nt_kit.zip

contains

"HP20b original ROM.bin"

which is 128KB in size (not 112KB--that is it includes the bootloader).

Have you tried flashing that to get your 20B's functional again?

A1

PS: The package also includes a PC version of the example HP20b application. Being a MFC (Microsoft Foundation Class) program it'll run in Windows 2000 and later.

PPS: I found and downloaded the Atmel AT91SAM7L128 datasheet (PDF) and the bootloader is in ROM (12KB) so it cannot be erased. The flash is 128KB.

[Maximilian Hohmann]

Hello!

(10-01-2024 05:47 PM)AnnoyedOne Wrote:  I haven't given up--yet

Very good - I appreciate that!

(10-01-2024 05:47 PM)AnnoyedOne Wrote:  The HP-20B "development kit" ... "HP20b original ROM.bin"

Thanks for the hint, I overlooked that.

(10-01-2024 05:47 PM)AnnoyedOne Wrote:  Have you tried flashing that to get your 20B's functional again?

Just tried it now, two or three times with each of my two HP-20b test objects, using the wp34sflash.app on my MacBook pro. The flashing procedure runs through each time and produces the same error message each time (see below). The calculators however work perfectly well in their native HP-20b mode after flashing despite the error message and pass their self-tests.
Very strange! This means that the cable, the flashing software and the USB-serial adapter all seem to work fine. But why is it not able to install the WP34s / WP31s firmware?

Regards
Max

[AnnoyedOne]

(10-02-2024 01:32 PM)Maximilian Hohmann Wrote:  But why is it not able to install the WP34s / WP31s firmware?

I think "packet 511" is the last one. Timing issue due to 32kHz crystal mod?

Scheisse!

A1

[Maximilian Hohmann]

Hello!

(10-02-2024 01:42 PM)AnnoyedOne Wrote:  Did you try "HP20b original ROM.bin"?

Yes, this is the message that I get when flashing that binary file.

(10-02-2024 01:42 PM)AnnoyedOne Wrote:  I think "packet 511" is the last one. Timing issue due to 32kHz crystal mod? What about your other 20b?

There is no difference between flashing the two calculators, the one with an added crytal and the original one. I will try the procedure from a windows calculator this evening using MySamba.

Regards
Max

[AnnoyedOne]

(10-02-2024 01:50 PM)Maximilian Hohmann Wrote:  I will try the procedure from a windows...

That was my next suggestion. MySamba should run on XP.

A1

PS: There's also the sample application in the above package. Not a calculator but much smaller.

PPS: From my brief reading of the AT91SAM7L128 datasheet the flash MUST be erased again before re-flashing. That is ERASE and RESET button presses between attempts.

[rprosperi]

There are many (!) versions of MySamba floating around and many are not compatible. For example, the MySamba used for the 15c CE is definitely NOT compatible with flashing the WP34S.

Attached below is a version which definitely IS compatible, and was modified by Marcus (on the WP34S team) to operate much more quickly the original Atmel version.

[AnnoyedOne]

(10-02-2024 04:32 PM)rprosperi Wrote:  For example, the MySamba used for the 15c CE is definitely NOT compatible with flashing the WP34S.

Correct. I think Atmel or Microchip changed the name of the software from "MySamba" (old version) to SAM-BA. I've used SAM-BA 2.16 (with my HP-15C CE) but not MySamba.

Again I have nothing based on the AT91SAM7L128. All I can do is download and read and offer insights based on my experiences.

A1

PS:

(10-02-2024 04:32 PM)rprosperi Wrote:  Attached below is a version which definitely IS compatible...

Thanks. Saved "just in case" I ever need it.

[Maximilian Hohmann]

Hello!

(10-02-2024 01:55 PM)AnnoyedOne Wrote:  That was my next suggestion. MySamba should run on XP.

That did it! MySamba on Windows XP was able to flash the original firmware without an error message. After that, WP34s could be uploaded to both calculators, the one without and the other one with the crystal installed. Note that differently from the documention, after being flashed and reset, the calculator will not restart with the "Paul Walter"-screen but with "Erased".

So my conclusions are:

1. The combination of a USB-serial adapter with an FTDI chip and the new flashing cable for the HP-15C CE works well. The original cable for the serial port is definitely not required, nor is a computer with a hardware serial port.

2. Stick to Windows (XP I tried, maybe also later versions work but I did not try that yet) and MySamba. As a Macintosh user, wp34sflash.app would of course be my preference, but I had no success yet.

3. These calculators (HP-30b and HP-20b) really cannot be "bricked" with failed attempts at flashing. They may appear dead and unresponsive at times though. In this case, reset the calculator (by removing the batteries, pressing the onboard reset-button or the reset button of the flashing cable) and follow the procedure. There will be not display, but the calculator will do what it is supposed to do.

4. Never give up early but always ask the friendly forum members for advice. This guarantees 100% success :-)

Regards
Max

[AnnoyedOne]

Congratulations Max!

I've no idea why your Mac version of MySamba has issues but who cares?

A1

PS: BTW I have multiple PC's with "real" hardware serial ports. And yes I use them from time to time. A lot of stuff is still "serial" but USB has replaced most stuff. I also have a USB-RS-232 adapter.

[John Ioannidis]

(10-02-2024 04:32 PM)rprosperi Wrote:  There are many (!) versions of MySamba floating around and many are not compatible. For example, the MySamba used for the 15c CE is definitely NOT compatible with flashing the WP34S.

Attached below is a version which definitely IS compatible, and was modified by Marcus (on the WP34S team) to operate much more quickly the original Atmel version.

We are all friends here (I hope; plus, you and I have interacted in the past, if this kind of endorsement is worth the bits it's written on ), but suggesting that people install random binaries is just promoting bad security habits. Remember: even paranoids have enemies!

Worse, the flashing tools in https://sourceforge.net/projects/wp34s/files/FlashTool/ come with no source code. I can't really imagine that whoever wrote them think that code has any commercial value, so why not provide the source?

FWIW, the actual SAM-BA software (not to be confused with samba, the open-source implementation of Microsoft's SMB/CIFS protocol!) is now at version 3.8, at https://www.microchip.com/en-us/developm...programmer

/ji

[brouhaha]

(10-02-2024 09:17 PM)John Ioannidis Wrote:  FWIW, the actual SAM-BA software (not to be confused with samba, the open-source implementation of Microsoft's SMB/CIFS protocol!) is now at version 3.8, at https://www.microchip.com/en-us/developm...programmer

Version 3.x will not work for flashing HP calculators, as Microchip/Atmel removed support for many chips. You have to use version 2.x. IIRC, x >= 18 or so.