I've made a snapshot of the lvm so I could work with a clone but now I see a even worst scenario!
Manual pygrub returns this:
sing <class 'grub.GrubConf.Grub2ConfigFile'> to parse /boot/grub/grub.cfg                                           Â[2/1801]
WARNING:root:Unknown directive menuentry_id_option
WARNING:root:Unknown directive else