Metal-type Printing of the Sangjeong gogeum yemun
Yi Gyu-bo’s collected works record that, after the move to Ganghwa, 28 copies of the ritual code Sangjeong gogeum yemun were printed with metal type. No copy survives.

Jjw · CC BY-SA 4.0 · Source
The Sangjeong gogeum yemun was a 50-volume compendium of rites compiled under King Injong by Choe Yun-ui and others. In a colophon written on Choe U’s behalf, Yi Gyu-bo explains that the original nearly perished in the move to Ganghwa and that from the surviving copy "28 copies were printed with cast type" and distributed to government offices. The printing is usually dated to about 1234, though some place it more broadly between 1234 and 1241.
If the record is accurate, it predates the Jikji (1377) by some 140 years, but with no surviving copy it cannot be confirmed.