Blank Upgrade

The Blank Upgrade is a craft component used in every upgrade recipe.

Recipe

The item in the middle is an extension card, which can be crafted this way:

The extension card can ONLY be crafted if you have completed the "Reverse Engineering" advancement, which consists in dropping a minePad from a high place (it has to fall for at least 20 blocks). This can be disabled in the configuration file by turning off hard recipes. If you attempt to craft an extension card while the "Reverse Engineering" advancement is incomplete, you will fail and get a Bad Extension Card.