grab the one from the original package for your board version and overwrite it. Then copy the whole card on the HD, format, and recopy the whole thing from the HD to the SD without drag and drop, just copy / paste.
You can edit in place the contents of that file but your multiple overwritting has probably modified the file structure on the SD, hence reformat and re install it all. That should solve your problem.
once jumping on the font menu, and select / boot a new one, the selected one will be written in that file, at the condition that it's structure isn't damaged.