---
title: "W7100-S2E MAC Id changed to FFFFFFFF"
url: "https://maker.wiznet.io/forum/11642"
markdown_url: "https://maker.wiznet.io/forum/11642/md"
type: "Forum topic"
category: "MCU & Boards"
author: "shabbir"
created: "2016-02-03T11:48:54+09:00"
last_activity: "2017-05-04T08:38:44+09:00"
language: "en"
views: 914
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W7100-S2E MAC Id changed to FFFFFFFF

## Question

Asked by shabbir on 2016-02-03 in MCU & Boards.

Hi,

I am using W7100-S2E with wiz107sr Firmware in my Design. ver 4.04.
Board working fine but suddenly i see that MAC address reset to FFFFFFFF… .
how can i recover the MAC? is any way i can re write the MAC ID?

Regards
shabbir

## Replies

### Reply 1 by jameskim, 2016-04-28

Hello,

Refer to the below link.
[url][Problem with Wiz107SR: not found by configuration tool after firmware upgrade](https://forum.wiznet.io/t/problem-with-wiz107sr-not-found-by-configuration-tool-after-firmware-upgrade/2252/1)]

You can solve the problem with this, I think.

BR,

Javakys.

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Source: https://maker.wiznet.io/forum/11642