I think i Fcked up my black 2 save file (I need help)

[ilyesrfs]

So I wanted to lend my cartridge of pokemon black 2 to a friend so he can experience what the best game on ths planet is, but I didnt wanted to delete my saved file, so i used checkpoint and i tested if it was working before to totally delete my save, and it worked so i deleted my save on my cartridge but kept the checkpoint one in the app. Now that he gave it back to me i tried to restore the file but it doesnt work. I need help plz (The file that i linked is the backup that was made with checkpoint)

POKEMON B2.sav