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"Magic key" during Inquiry #4

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MDJRosenau opened this issue Mar 10, 2024 · 3 comments
Open

"Magic key" during Inquiry #4

MDJRosenau opened this issue Mar 10, 2024 · 3 comments
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@MDJRosenau
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Hello Martin

I'm interested in the protocol because the Yamaha app does not run on the operating system I am using.

I have a question about the "magic key" in the "activate MIDI" message:

In the Windows app, there are three binary files which are obviously symbol tables of different firmware versions.

I found out that the CRC-32 values of three of these files are identical to three of the "magic keys" listed in your PDF.

For this reason, I think that the "activate MIDI" message is actually there to ensure that the app uses the correct symbol table if it does not read this table from the device.

If this is the case, the "magic key " of future firmware versions could be calculated by calculating the CRC-32 of the symbol table.

MY QUESTION:

... this would require reading the symbol table before sending the "activate MIDI" message.

In your PDF you write: "Do not send any commands to the THRII before successful MIDI activation- or you get stuck!"

What exactly happened when you tried to send SYSEX messages before the "activate MIDI" message?

Did you brick your amplifier or did you just have to do a power-on/off reset to get the amplifier working again?

I don't like to try reading out the symbol table before sending the "activate MIDI" message if I know that sending SYSEX messages before the "activate MIDI" message bricks the device...

Thanks for your Answer

Martin

@martinzw
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martinzw commented Mar 10, 2024 via email

@MDJRosenau
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I just tested with my THR-10-II, firmware 1.44.0a:
Reading the symbol table works before sending the "activate MIDI" message.
... and the CRC-32 of the symbol table matches the key.

@martinzw
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martinzw commented Mar 11, 2024 via email

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