Big files are zipped and need to be extracted to your usb ,maybe when done it will show as a cndf file?
had another read.
" For BM7000 get the program NDFEdit from this site. For BM8000 get the program DBMEdit from this site. These programs are Windows only. You can easily convert an existing CDF file to a DBM file by first loading the CDF file into DBMEdit, and then simply SAVE AS a new name. This allows users to use their favorite CDF editor program and then convert it to DBM format. "