[LAD] Looking for interested developer - TonePrint editor & TC Electronic Plethora X5

[Sam Kuper]

On Thu, May 28, 2020 at 07:08:25AM -0700, Mark Knecht wrote:
> On Thu, May 28, 2020 at 4:31 AM Sam Kuper wrote:
>> On Tue, May 26, 2020 at 04:57:14PM -0700, Mark Knecht wrote:
>> > I purchased [a TC Electronic Plethora X5]. It works well (so far).
>> > It's Linux internally running 4.9.47-rt37.
>>
>> I'm curious: how do you know which kernel your Plethora X5 uses?
> 
> The front panel menu system:
> 
> Global->About->BSP-> Linux 4.9.47-rt37 2019-12-20.C23818C

Thanks.


>> Finally, do you know if TC Electronic has published any of the source
>> code relevant to the Plethora X5?
> 
> I haven't looked hard for any of that but I also haven't seen it in the
> manual or on their website.

Thanks.  All I could find on the TC Electronic website was this page,
which attempts to foist an EULA on anyone who downloads the firmware:
https://www.tcelectronic.com/Categories/Tcelectronic/Guitar/Effects-Processors/PLETHORA-X5/p/P0D9M/Downloads

I've sent an email to license-violation at gpl-violations.org to let
them know.

I'm not sure it would be wise for anyone to spend time trying to
reverse-engineer the X5 if its source code might be forthcoming.  Trying
to get the source code seems a better use of effort in the first
instance.

(N.B.: I do not know whether TC Electronic is in fact violating the GPL,
nor whether it will ever publish its source code for the X5.  Sadly, nor
can I help on that front beyond what I have already done, since I don't
hold copyright on any code in the Linux kernel nor do I own an X5.  My
participation in this email thread has been on the basis that I would
like to see more audio equipment running and/or made compatible with
GNU/Linux, and on the basis that if the X5 were made more interoperable
with GNU/Linux then I might be interested in owning one.)


> mark at science:~$ diff /tmp/lsusb_x5_disconnected.txt
> /tmp/lsusb_x5_connected.txt
> 10a11,13
>>     |__ Port 2: Dev 3, If 0, Class=Audio, Driver=snd-usb-audio, 480M
>>     |__ Port 2: Dev 3, If 1, Class=Audio, Driver=snd-usb-audio, 480M
>>     |__ Port 2: Dev 3, If 2, Class=Mass Storage, Driver=usb-storage, 480M
> mark at science:~$
> 
> In Windows when you plug the device in your get a explorer window.
> Dropping a firmware update into that window and power cycling does the
> firmware upgrade automatically.

Thanks.

Since the X5 presents a USB mass storage device to the OS and uses
that to upgrade the firmware, at least you should be able to upgrade the
X5's firmware from your GNU/Linux box.

That firmware upgrade path might provide opportunities for future
reverse engineering attempts.   (In addition to searching the PCB for
JTAG headers, etc.)

I wonder how the Windows software communicates with the X5, though.
That's not obvious from the lsusb output.  A reverse engineer might need
to intercept/sniff the USB traffic between the X5 and a Windows host to
figure that out.


> A first response from TC Electronic via a moderator named 'TC-Mike' is
> that the ability to backup the device is 'on the roadmap'.
> 
> I asked about general timeframe but have received no response.

Thanks for the follow-up.


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