diff --git a/scripts/imgtool/image.py b/scripts/imgtool/image.py
index 115d04ec9..5fec3c1b7 100644
--- a/scripts/imgtool/image.py
+++ b/scripts/imgtool/image.py
@@ -184,6 +184,7 @@ def tlv_sha_to_sha(tlv):
     keys.ECDSA384P1Public   : ['384'],
     keys.ECDSA256P1         : ['256'],
     keys.RSA                : ['256'],
+    keys.RSAPublic          : ['256'],
     # This two are set to 256 for compatibility, the right would be 512
     keys.Ed25519            : ['256', '512'],
     keys.X25519             : ['256', '512']