A couple of rabbits skinned and dried - a few stitches and not a bad pair of shoes - cosy too. Reliance on anything will impede survival the best bet
will always be adaptation and improvisation. Just don't forget to pack the knife AND the needle.
Any soft items such as windblown grasses, cattail down, a compressed hive, dry moss leaves, etc., will soften and protect the foot. Secondly, for the outer layer and a means of engulfing the foot, this is accomplished with sheets of birch bark, a slab of willow bark, a woven reed or birch layered mats, any firm encompassing material that is durable for a short time solution.
To keep these protective layers securely on the foot, any lashing items will suffice. This can come from a belt, string, duct tape or even a roller bandage. Maybe yarn from your sweater woven into cordage, a spruce root, making birch bark cord and many more options will give the securing needed.