# fwupdateDownloader sample app

**URL:** <https://forum.legato.io/t/fwupdatedownloader-sample-app/6465>\
**Category:** Legato Application Framework\
**Created:** [March 21, 2023, 4:32pm UTC](https://forum.legato.io/t/fwupdatedownloader-sample-app/6465 "2023-03-21T16:32:14Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [March 21, 2023, 4:36pm UTC](https://forum.legato.io/t/fwupdatedownloader-sample-app/6465/2 "2023-03-21T16:36:18Z")

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I have modified the app as TCP server and tried in USB ECM interface, it was working fine:

> [@Networking: TCP server Operation not permitted (errno -1)](https://forum.legato.io/t/networking-tcp-server-operation-not-permitted-errno-1/4650/4):
>
> You can use my TCP echo server application which uses read() instead of recv(). Procedure: compile and download attached application iptables -I INPUT -j ACCEPT app start fwupdateDownloader in Linux PC, type “nc 192.168.2.2 5000” after connected, you can type some characters and the application will echo back to linux PC. [fwupdateDownloader.rar](https://forum.legato.io/uploads/short-url/rtNMsZzuYC3CC0QmrsWh0EfadIR.rar) (174.0 KB)

You can set up TCP server on port 5000 by this nc binary to see if you can connect from outside:

```auto
chmod 777 ./nc
./nc -l -p 5000

```

[nc](https://forum.legato.io/uploads/short-url/a2ZtPIhRFpHfkCiSnt4OAy3o1Ia) (756.4 KB)

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