Switch Keys 1602zipertozip -

1602 could mean (YYYYMM format reversed). That predates the Switch launch (March 2017). Thus, no official keys exist from that period.

Run the payload tool called Lockpick_RCM . switch keys 1602zipertozip

This usually means your keys are outdated. Ensure you are using the 16.0.2 keys specifically. 1602 could mean (YYYYMM format reversed)