diff --git a/src/erc7730/convert/convert_eip712_to_erc7730.py b/src/erc7730/convert/convert_eip712_to_erc7730.py
index 11f23df..612aa77 100644
--- a/src/erc7730/convert/convert_eip712_to_erc7730.py
+++ b/src/erc7730/convert/convert_eip712_to_erc7730.py
@@ -10,6 +10,9 @@
 from eip712 import (
     EIP712Format as LegacyEIP712Format,
 )
+from eip712 import (
+    EIP712MessageDescriptor as LegacyEIP712MessageDescriptor,
+)
 from pydantic import AnyUrl
 
 from erc7730.common.output import OutputAdder
@@ -53,9 +56,8 @@ def convert(
                 # TODO improve typing on EIP-712 library
                 schema = typing.cast(dict[str, list[EIP712Field]], message.schema_)
                 mapper = message.mapper
-                # FIXME this is wrong,
-                #  see https://github.com/LedgerHQ/clear-signing-erc7730-registry/pull/21/files#r1785706984
-                primary_type = mapper.label
+                # TODO make this public on EIP-712 library
+                primary_type = LegacyEIP712MessageDescriptor._schema_top_level_type(schema)
                 schemas.append(EIP712JsonSchema(primaryType=primary_type, types=schema))
                 fields = [self._convert_field(field) for field in mapper.fields]
                 formats[primary_type] = InputFormat(intent=None, fields=fields, required=None, screens=None)