Arc Kobo ARC 10 HD in bootloop

[bapheus]

My Kobo ARC 10 HD is in bootloop after firmware udpate from sideload and cache wipe.

Hardware functioning (disassembled and verified components)

Can access to recovery with only this options:

reboot system now
apply update from ADB
wipe data/factory reset
wipe cache partition

The device is NOT rooted, USB debugging NOT active; I never tried to modify any of the factory settings.

I tried factory reset but ineffectual.

I have installed via adb sideload macallan-ota-932.zip downloaded from this link

http://www.mediafire.com/file/6nwyrn...a-932.zip/file

installation successeful but didn't solved the problem.

I think the OS don't mounts the partitions and the factory reset don't wipe all the memory. I used Linux for years but don't know much of android and, so far, I hate it.

In normal boot the pc recognize the the device as MTP USB Android and the memory is inaccessible.

In Recovery mode the pc recognise the kobo arc 10 but only in adb sideload (adb shell and adb fastboot unusable).

There is a method, in this conditions, to erase/format the device memory and reinstall a functioning original Stock ROM (and where to download it)?

There are some alternative methods I don't know can use?

I have read yet all the posts on this subject in this forum and xda developers.

Thanks for help and sorry for my english.