diff --git a/cmd/bucket-policy-handlers.go b/cmd/bucket-policy-handlers.go
index 6350f1ef3..277ec5da5 100644
--- a/cmd/bucket-policy-handlers.go
+++ b/cmd/bucket-policy-handlers.go
@@ -86,7 +86,11 @@ func (api objectAPIHandlers) PutBucketPolicyHandler(w http.ResponseWriter, r *ht
 
 	bucketPolicy, err := policy.ParseConfig(bytes.NewReader(bucketPolicyBytes), bucket)
 	if err != nil {
-		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
+		writeErrorResponse(ctx, w, APIError{
+			Code:           "ErrMalformedXML",
+			HTTPStatusCode: http.StatusBadRequest,
+			Description:    err.Error(),
+		}, r.URL)
 		return
 	}
 
diff --git a/cmd/kms-handlers.go b/cmd/kms-handlers.go
index ba60ca13d..321358ea7 100644
--- a/cmd/kms-handlers.go
+++ b/cmd/kms-handlers.go
@@ -82,6 +82,11 @@ func (a kmsAPIHandlers) KMSMetricsHandler(w http.ResponseWriter, r *http.Request
 		return
 	}
 
+	if _, ok := GlobalKMS.(kms.KeyManager); !ok {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrNotImplemented), r.URL)
+		return
+	}
+
 	metrics, err := GlobalKMS.Metrics(ctx)
 	if err != nil {
 		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
diff --git a/cmd/metacache-server-pool.go b/cmd/metacache-server-pool.go
index 38cbff39e..61402f093 100644
--- a/cmd/metacache-server-pool.go
+++ b/cmd/metacache-server-pool.go
@@ -316,11 +316,11 @@ func (z *erasureServerPools) listMerged(ctx context.Context, o listPathOptions,
 	}
 
 	for _, err := range errs {
-		if err == nil || contextCanceled(ctx) {
-			allAtEOF = false
+		if errors.Is(err, io.EOF) {
 			continue
 		}
-		if err.Error() == io.EOF.Error() {
+		if err == nil || contextCanceled(ctx) || errors.Is(err, context.Canceled) {
+			allAtEOF = false
 			continue
 		}
 		logger.LogIf(ctx, err)
diff --git a/cmd/metacache-set.go b/cmd/metacache-set.go
index cce78e24d..2d804f82e 100644
--- a/cmd/metacache-set.go
+++ b/cmd/metacache-set.go
@@ -376,7 +376,7 @@ func (r *metacacheReader) filter(o listPathOptions) (entries metaCacheEntriesSor
 			entries.o = append(entries.o, entry)
 			return entries.len() < o.Limit
 		})
-		if (err != nil && err.Error() == io.EOF.Error()) || pastPrefix || r.nextEOF() {
+		if (err != nil && errors.Is(err, io.EOF)) || pastPrefix || r.nextEOF() {
 			return entries, io.EOF
 		}
 		return entries, err
@@ -534,7 +534,7 @@ func (er *erasureObjects) streamMetadataParts(ctx context.Context, o listPathOpt
 				// We stopped within the listing, we are done for now...
 				return entries, nil
 			}
-			if err != nil && err.Error() != io.EOF.Error() {
+			if err != nil && !errors.Is(err, io.EOF) {
 				switch toObjectErr(err, minioMetaBucket, o.objectPath(partN)).(type) {
 				case ObjectNotFound:
 					retries++
@@ -940,15 +940,6 @@ func listPathRaw(ctx context.Context, opts listPathRawOptions) (err error) {
 				}
 			}
 			w.CloseWithError(werr)
-
-			if werr != io.EOF && werr != nil &&
-				werr.Error() != errFileNotFound.Error() &&
-				werr.Error() != errVolumeNotFound.Error() &&
-				werr.Error() != errDiskNotFound.Error() &&
-				werr.Error() != errUnformattedDisk.Error() &&
-				!errors.Is(werr, context.Canceled) {
-				logger.LogIf(ctx, werr)
-			}
 		}()
 	}
 
diff --git a/internal/kms/single-key.go b/internal/kms/single-key.go
index bfd8aceca..59f2299d7 100644
--- a/internal/kms/single-key.go
+++ b/internal/kms/single-key.go
@@ -91,12 +91,15 @@ func (kms secretKey) Stat(context.Context) (Status, error) {
 	}, nil
 }
 
-func (secretKey) Metrics(ctx context.Context) (kes.Metric, error) {
-	return kes.Metric{}, errors.New("kms: metrics are not supported")
+func (secretKey) Metrics(context.Context) (kes.Metric, error) {
+	return kes.Metric{}, errors.New("kms: metrics not supported")
 }
 
-func (secretKey) CreateKey(context.Context, string) error {
-	return errors.New("kms: creating keys is not supported")
+func (kms secretKey) CreateKey(_ context.Context, keyID string) error {
+	if keyID == kms.keyID {
+		return nil
+	}
+	return fmt.Errorf("kms: creating custom key %q is not supported", keyID)
 }
 
 func (kms secretKey) GenerateKey(_ context.Context, keyID string, context Context) (DEK, error) {