diff --git a/scripts/imgtool/keys/ed25519.py b/scripts/imgtool/keys/ed25519.py
index 57eb99a..6745a89 100644
--- a/scripts/imgtool/keys/ed25519.py
+++ b/scripts/imgtool/keys/ed25519.py
@@ -32,6 +32,9 @@
                 encoding=serialization.Encoding.DER,
                 format=serialization.PublicFormat.SubjectPublicKeyInfo)
 
+    def get_private_bytes(self, minimal):
+        self._unsupported('get_private_bytes')
+
     def export_private(self, path, passwd=None):
         self._unsupported('export_private')
 
@@ -70,6 +73,10 @@
     def _get_public(self):
         return self.key.public_key()
 
+    def get_private_bytes(self, minimal):
+        raise Ed25519UsageError("Operation not supported with {} keys".format(
+            self.shortname()))
+
     def export_private(self, path, passwd=None):
         """
         Write the private key to the given file, protecting it with the