Clara HD SD card empty after failed start

Hi,

I've searched existing threads but I didn't find any similar fail on Kobo Clara HD reported on the forum.
After a failed start, SD card was erased on my ereader. The ereader doesn't start now and I always have the 3 dots screen. Even after charging the battery at full capacity.
I have tried all the resest procedures provided by Kobo on their official website in vain.
Now when I connect the SD card on my desktop computer through an adaptator I don't have the .kobo directory. See screenshot. When I try to repair the SD card on disk utility (I use Macos), the process goes well but I still can't start the ereader.
How can I fix the SD card and start again the ereader ?
I have talked to Kobo and they don't do any maintenance on their ereaders. They only propose me to buy a new one... (no comment).
The screen is perfect and I don't have the intention to buy another one.
I've read some articles on other websites where the process seemed to be always related with the .kobo directory, which I don't have anymore on the SD card. So I'm stucked.

Thanks in advance for your help.

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