Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a synchronization signal block (SSB) transmitted by a base station. The UE may receive system information that includes reconfigurable intelligent surface (RIS) or repeater assisted initial access information that identifies a set of SSBs that are associated with an RIS or a repeater and a modulation signature associated with the RIS or the repeater. The UE may selectively perform initial access using the SSB or search for another SSB based at least in part on the RIS or repeater assisted initial access information. Numerous other aspects are described.