diff --git a/packages/unified_mnemonic/pubspec.yaml b/packages/unified_mnemonic/pubspec.yaml
index f4357fb..e30c2db 100644
--- a/packages/unified_mnemonic/pubspec.yaml
+++ b/packages/unified_mnemonic/pubspec.yaml
@@ -19,6 +19,6 @@ dependencies:
   # path: ^1.8.0
 
 dev_dependencies:
-  ffigen: ^8.0.2
+  ffigen: ">=8.0.2 <10.0.0"
   lints: ^2.0.0
   test: ^1.21.0