L1 concepts/formulas on L2 test?

L2 is ‘independent’ from L1 in the sense that they won’t be asking questions directly taken from the L1 CFA Institute curriculum. However, L2 curriculum assumes (correctly) you’ve completed and passed L1, so calculations and concepts assume knowledge of L1 material.

For review of L1 in preparation for L2, usually secret sauce / 11th hour books are enough. Sometimes providers also include a ‘quick recap’ book in their materials for this purpose.