tiffsplit program from the LibTIFF library does a good job of splitting multi-page TIFF files into single pages. It doesn’t seem that great at handling TIFFs saved with ‘old-style’ JPEG encoding.
It’ll produce files, and the correct number of files too, but the files are actually in JPEG format. Most image viewers won’t open them still because they’re JPEG files with TIFF headers.
Assuming you have a TIFF file made up entirely of old-style JPEG encoded images you can loop through the files that
tiffsplit has exported and remove the first eight bytes to give valid JPEG files.