diff --git a/internal/checker/checker.go b/internal/checker/checker.go
index 5d324795d..df865cb41 100644
--- a/internal/checker/checker.go
+++ b/internal/checker/checker.go
@@ -14,7 +14,6 @@ import (
 	"github.com/minio/sha256-simd"
 	"github.com/restic/restic/internal/backend"
 	"github.com/restic/restic/internal/backend/s3"
-	"github.com/restic/restic/internal/cache"
 	"github.com/restic/restic/internal/debug"
 	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/hashing"
@@ -241,17 +240,8 @@ func IsOrphanedPack(err error) bool {
 }
 
 func isS3Legacy(b backend.Backend) bool {
-	// unwrap cache
-	if be, ok := b.(*cache.Backend); ok {
-		b = be.Backend
-	}
-
-	be, ok := b.(*s3.Backend)
-	if !ok {
-		return false
-	}
-
-	return be.Layout.Name() == "s3legacy"
+	be := backend.AsBackend[*s3.Backend](b)
+	return be != nil && be.Layout.Name() == "s3legacy"
 }
 
 // Packs checks that all packs referenced in the index are still available and