зашнуровать and расшнуровать ...
If I'm not mistaken, when tying the shoes, one says either завязать шнурки or зашнуровать туфли/ботинки (but not зашнуровать шнурки) -- is that right?
расшнуровать / зашнуровать - are used when a shoelace is taken totally out (or inserted in the lace holes when it was totally out) of the shoe.