# Eth0 does not always appear & requires a power cycle if not present

**URL:** <https://forum.legato.io/t/eth0-does-not-always-appear-requires-a-power-cycle-if-not-present/6509>\
**Category:** Legato Linux distribution (Yocto project)\
**Created:** [May 22, 2023, 4:31pm UTC](https://forum.legato.io/t/eth0-does-not-always-appear-requires-a-power-cycle-if-not-present/6509 "2023-05-22T16:31:06Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![sierra](https://avatars.discourse-cdn.com/v4/letter/s/4da419/32.png) [@sierra](https://forum.legato.io/u/sierra)\
**Post date:** [May 22, 2023, 4:31pm UTC](https://forum.legato.io/t/eth0-does-not-always-appear-requires-a-power-cycle-if-not-present/6509/1 "2023-05-22T16:31:06Z")

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I have a MangOH yellow board with a talon ethernet board plugged into the IoT connector.  
Most of the time this works fine. Occasionally it forgets that it has an ethernet connection. When this happens, the only way I have found to get it to work again is to power cycle the MangOH.  
Are there any better solutions to this problem?

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**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.legato.io/jyijyi/32/822_2.png) [@jyijyi](https://forum.legato.io/u/jyijyi)\
**Post date:** [May 22, 2023, 5:11pm UTC](https://forum.legato.io/t/eth0-does-not-always-appear-requires-a-power-cycle-if-not-present/6509/2 "2023-05-22T17:11:40Z")

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Could it be some IOT card hardware connection problem?

> **[Setting up MangOH Red as Router to Cellular Gateway](https://forum.mangoh.io/t/setting-up-mangoh-red-as-router-to-cellular-gateway/1241)**
>
> Objective: Configure a MangOH to route cellular internet data to/from other network interfaces. For example the image below shows how we will route traffic to/from the ethernet IoT slot to/from the cellular gateway. Solution: To configure...

Is that there is a reset pin on the board?

> **[WP7702 how to enable ethernet IoT card?](https://forum.mangoh.io/t/wp7702-how-to-enable-ethernet-iot-card/5001)**
>
> I have a mangoh red with a wp7702 module, everything is pretty much set up and each step in the getting started guide has been completed successfully. Now I have an ethernet expansion card made by Talon Communications for the IoT CN306 header and...

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**Author:** ![sierra](https://avatars.discourse-cdn.com/v4/letter/s/4da419/32.png) [@sierra](https://forum.legato.io/u/sierra)\
**Post date:** [May 23, 2023, 9:17am UTC](https://forum.legato.io/t/eth0-does-not-always-appear-requires-a-power-cycle-if-not-present/6509/3 "2023-05-23T09:17:36Z")

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Thanks for the prompt reply.  
The board appears to have connections to the following IoT pins:  
2: USB-D+  
3: USB-D-  
4/21/30/38: Gnd  
11: Vcc 1v8 ULPM  
22: SDA  
23: SCL  
28/29: 3v3  
31: Card Detect  
32: Reset

The shell script from the link would run to the lines  
if [[! -d /sys/class/net/${ITF\_LAN}]]; then  
echo “Bring up LAN interface $ITF\_LAN”  
/sbin/ifup $ITF\_LAN  
if [“$?” -ne 0]; then  
echo “Bring up LAN interface $ITF\_LAN failed”  
exit 1  
fi  
fi

Where is would exit with:  
ifconfig: SIOCGIFFLAGS: No such device  
ifconfig: SIOCSIFADDR: No such device

Dave.

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<div class="post-metadata">

**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.legato.io/jyijyi/32/822_2.png) [@jyijyi](https://forum.legato.io/u/jyijyi)\
**Post date:** [May 23, 2023, 9:19am UTC](https://forum.legato.io/t/eth0-does-not-always-appear-requires-a-power-cycle-if-not-present/6509/4 "2023-05-23T09:19:13Z")

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how about re-insert the IOT card?  
How about toggling the reset pin?