diff --git a/src/chains/ethereum/transaction/src/hardfork.ts b/src/chains/ethereum/transaction/src/hardfork.ts
index 03ee38115f..fcd4506ce6 100644
--- a/src/chains/ethereum/transaction/src/hardfork.ts
+++ b/src/chains/ethereum/transaction/src/hardfork.ts
@@ -9,4 +9,5 @@ export type Hardfork =
   | "arrowGlacier"
   | "grayGlacier"
   | "merge"
+  | "mergeForkIdTransition"
   | "shanghai";
diff --git a/src/chains/ethereum/transaction/src/params.ts b/src/chains/ethereum/transaction/src/params.ts
index d1e6decb94..b14ea30013 100644
--- a/src/chains/ethereum/transaction/src/params.ts
+++ b/src/chains/ethereum/transaction/src/params.ts
@@ -29,6 +29,7 @@ export const Params = {
     | "arrowGlacier"
     | "grayGlacier"
     | "merge"
+    | "mergeForkIdTransition"
     | "shanghai",
     bigint
   >([
@@ -47,6 +48,7 @@ export const Params = {
     ["arrowGlacier", 16n],
     ["grayGlacier", 16n],
     ["merge", 16n],
+    ["mergeForkIdTransition", 16n],
     ["shanghai", 16n]
   ]),