
I confess I was rather nervous !
As my ebooks make a size, now, I had prepared a copy of all the other folders, and an empty eBooks folder, to paste a complete tree but as small as possible !
Then, I tried with that, and my sighs of relief was a biiig one, when first it started normally, and second kept its configuration when restarted !

I only had, then, to paste all my ebooks in their folders !
Now I know it's possible, it's pretty interesting that a restore is so simple !