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Stand-alone/self-hosted configuration
#21
(04-Jan-2015, 18:40)thumb5 Wrote: Ah, that's very interesting: I thought that editing the config file by hand wouldn't work because the file was protected by a CRC. To be more specific, I had assumed that if one changed the file by hand the amplifier could detect that its contents didn't match the CRC and would therefore refuse to load it.

If you're speaking from experience of making a hand-edit and having it load into the amplifier and work as expected, that would make me feel a lot less uncomfortable.

thumb5, you were right! my bad Blush

the CRC check failed the file, the D unit refused to load and the display showed a message saying a corrupt config file!
Aurender X100L / Transrotor Crescendo TT / Denon DCD1520 / Macbook Pro >> D400 >> Martin Logan Montis
amabrok's system - Latest update (May 2015, Page 11, Post #109)

Dubai, UAE
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#22
(04-Jan-2015, 18:57)IanG-UK Wrote: This was a quote from Mathias Pernot (Devialet's senior engineer) in relation to the D-Premier:

"It is true that sending the security pass for one's WiFi network over the Internet is not the most advisable practice even though realistically speaking, most security schemes today have been found to be easily hackable quite fast. To work around this issue yet maintain the ability to provide the D-Premier with a key so it can join the network, we've implemented another entry method similar to the one you mentioned. If you edit the configuration text file to change any parameter, the altered file will most likely be rejected by the D-Premier thanks to a CRC (check sum) key located on top of it which gets properly computed by the configurator and accordingly checked by the D-Premier.

I had added this validation mechanism to prevent uninformed users from breaking their hardware with inconsistent parameter values like those related to the power supply even if we have additional security checks. I think it really makes sense for that reason."

hi Ian, it was my understanding that the Wifi block of the config file was not used in the CRC calculation, for user privacy to allow users to hand-edit at home just the SSID and Wifi password.

At the time this was all introduced, it was somebody on Computer Audiophile who complained to Devialet after they initially put these items into the Configurator. Very shortly afterwards they allowed these to be excluded and updated the firmware.

I've not kept up with this so its possible that the approach is now different, but AFAIK it should still be possible to setup a config file with no Wifi details, and then edit them by hand later without invalidating the CRC..... ?
 _________________________________________________________________________
Aurender X100, Audiophilleo, Devialet 200, Verity Audio Parsifal Ovation Monitors
Leiden, the Netherlands
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#23
(04-Jan-2015, 20:24)krass Wrote:
(04-Jan-2015, 18:57)IanG-UK Wrote: This was a quote from Mathias Pernot (Devialet's senior engineer) in relation to the D-Premier:

"It is true that sending the security pass for one's WiFi network over the Internet is not the most advisable practice even though realistically speaking, most security schemes today have been found to be easily hackable quite fast. To work around this issue yet maintain the ability to provide the D-Premier with a key so it can join the network, we've implemented another entry method similar to the one you mentioned. If you edit the configuration text file to change any parameter, the altered file will most likely be rejected by the D-Premier thanks to a CRC (check sum) key located on top of it which gets properly computed by the configurator and accordingly checked by the D-Premier.

I had added this validation mechanism to prevent uninformed users from breaking their hardware with inconsistent parameter values like those related to the power supply even if we have additional security checks. I think it really makes sense for that reason."

hi Ian, it was my understanding that the Wifi block of the config file was not used in the CRC calculation, for user privacy to allow users to hand-edit at home just the SSID and Wifi password.

At the time this was all introduced, it was somebody on Computer Audiophile who complained to Devialet after they initially put these items into the Configurator. Very shortly afterwards they allowed these to be excluded and updated the firmware.

I've not kept up with this so its possible that the approach is now different, but AFAIK it should still be possible to setup a config file with no Wifi details, and then edit them by hand later without invalidating the CRC..... ?

At present the safe procedure is to mark "Offline secure key" in the WiFi config of the configurator and to create a text file with the name "wifi_key.txt" and the only content being your WiFi password. This txt file should be on the card together with the "dp_cfg.txt" config file.

There is no editing of the "dp_cfg" config file involved. This would invalidate the config as mentioned by IanG.
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#24
That's very handy to know, thanks.
Roon (Mac Mini), Wilson Benesch Full Circle, Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
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