By (now classical) work of Fontaine and Laffaille, Galois stable Z_p-lattices in crystalline Galois representations of an unramified p-adic local field with Hodge--Tate weights between 0 and p-2 can be classified in terms of quite simple linear algebraic data involving filtered vector bundles over the ring of integers W(k), equipped with a suitable divided Frobenius structure compatible with Mazur--Ogus bounds for lattices of geometric origin. This story was recently reinterpreted by Terentiuk--Vologodsky--Xu (TVX) in terms of prismatic F-gauges over W(k), and the results of Fontaine--Laffaille recast in terms of the Bhatt--Scholze equivalence between such F-gauges (or prismatic F-crystals) and lattices in crystalline Galois representations. It turns out that a re-reinterpretation of the work of TVX makes sense over *any* p-adic formal base, giving a uniform classification of prismatic F-gauges---and hence by work of Guo--Reinecke and Pentland a classification of crystalline Z_p-local systems---within the Fontaine--Laffaille range. I will explain this story and its proof, which reduces to a concrete computation of the syntomic cohomology of F_p/^L p. This is joint work with Shubhodip Mondal.