Thanks a lot.
Of course I have a copy of librelec on another SD card.
Currently Libreelec 10 with the TVhat recorder works correctly, except :
1. I could not get the Catchup extension working like on more recent versions
2. sometimes recording of TV is not correct : a wrong channel is recorded. This is certainly related to the modification of the french channels. Yesterday I discovered an inactive parameter concerning the channel numbers. I still have to check the result on a future recording
Anyway I have a bad souvenir of installing TVhat...
To be followed..
Best regards