Why might the central unit of the DIS CU 5905 audio conferencing system not work?

Question

Do it yourself

Good afternoon fellow colleagues.
I ran into the following problem at work.
I have an audio conferencing system (microphones + control box) for the boardroom. All this is built on the basis of DIS products.
The problem is that for a year and a half everything worked fine, and today the microphones just simply stopped turning on.
I localized the problem in that the base unit does not work correctly. He is - DIS CU 5905 Central Unit .
The problem is as follows: the base unit properly shines with a green LED (when you press the on / off button, it changes its color to red). Those. pretends to work. However, the screen located on the block does not give out any information. Microphones connected to this block - refuse to respond to all buttons. Well, no sound comes out of it.
I called up the supplier - they said "Non-warranty case. Take it to the service center." As I understood from a conversation with a technical specialist of the supplier, the problem is not new and is known in the circles of users of this equipment.
That's just a service center in Moscow (from me it's about 1700 km.).
And there is a big suspicion that the problem is still software (perhaps something with the firmware of the device). You can connect to the device only through the web interface, but he does not want to receive Ip from DHCP.
Can anyone come across a similar one (or does anyone have this equipment). Let me know please.
PS:
The solution to my specific problem is described in the comment below.

Answer 1

I asked myself - I'll answer it myself, suddenly it will come in handy for someone.
In general, in my particular case, the problem really turned out to be software. Damaged (with a sudden power outage) boot script.
If you have the same problem (and you can localize it by glowing yellow diodes on the board with the SD card inside the CU), then do the following:
1. Contact the owners of the same equipment as you have.
2. Through goodies and cognac, ask them to disassemble your CU5905 and remove the SD card from it (great power of persuasion).
3. Ask them to make a complete image of the flash drive (you can byte by byte). It is the image, and not just copying the files (because there are hidden files there, and there seems to be a binding to sectors).
4. Restore to your flash drive (having previously disassembled the CU, pulled out the flash drive and inserted it into the card reader) the image sent to you.
5. Pray and run CU.
6. PROFIT???
PS:
Link to the archive with the image, instructions and program for recovery - https://yadi.sk/d/qQWSjc0Jsqw2U