From d559ce80c1314e9ddbe02798f1c61a2e8349da6e Mon Sep 17 00:00:00 2001
From: Daniel Wang <99078276+dantaik@users.noreply.github.com>
Date: Thu, 15 Aug 2024 14:24:20 +0800
Subject: [PATCH] fix(protocol): make sure new instance is not zero address in
 SgxVerifier (#17918)

---
 packages/protocol/contracts/verifiers/SgxVerifier.sol | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/protocol/contracts/verifiers/SgxVerifier.sol b/packages/protocol/contracts/verifiers/SgxVerifier.sol
index 3acba8ef0f6..b1971182022 100644
--- a/packages/protocol/contracts/verifiers/SgxVerifier.sol
+++ b/packages/protocol/contracts/verifiers/SgxVerifier.sol
@@ -170,7 +170,7 @@ contract SgxVerifier is EssentialContract, IVerifier {
 
         if (!_isInstanceValid(id, oldInstance)) revert SGX_INVALID_INSTANCE();
 
-        if (oldInstance != newInstance) {
+        if (newInstance != oldInstance && newInstance != address(0)) {
             _replaceInstance(id, oldInstance, newInstance);
         }
     }