# TySOM-3A-ZU19EG : PYNQ works but XRT doesn't on its own

**URL:** <https://discuss.pynq.io/t/tysom-3a-zu19eg-pynq-works-but-xrt-doesnt-on-its-own/8534>\
**Category:** Support\
**Created:** [June 10, 2025, 12:35pm UTC](https://discuss.pynq.io/t/tysom-3a-zu19eg-pynq-works-but-xrt-doesnt-on-its-own/8534 "2025-06-10T12:35:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Mousakaa](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/mousakaa/32/7090_2.png) [@Mousakaa](https://discuss.pynq.io/u/Mousakaa)\
**Post date:** [June 10, 2025, 12:35pm UTC](https://discuss.pynq.io/t/tysom-3a-zu19eg-pynq-works-but-xrt-doesnt-on-its-own/8534/1 "2025-06-10T12:35:43Z")

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I am using the PYNQ 3.0.1 image for the TySOM-3A-ZU1EG board provided by [TySOM-PYNQ](https://github.com/aldec/TySOM-PYNQ).

When using PYNQ, everything works flawlessly, but when I try to use XRT on its own through the C++ library, it doesn’t seem to detect any FPGA devices.

The problem arose while testing [this project](https://github.com/eki-project/finn-cpp-driver), which is a C++ version of the PYNQ-based FINN driver (`https://github.com/Xilinx/finn`). Here is the resulting error :

```sh
xilinx@pynq:~$ ./build/src/FINNCppDriver/finn --configpath yolo_config.json
Error: Could not open device with index '0'

```

It seems to be a problem with XRT since `xbutil examine` returns :

```sh
System Configuration
  OS Name : Linux
  Release : 5.15.19-xilinx-v2022.1
  Version : #1 SMP Mon Apr 11 17:52:14 UTC 2022
  Machine : aarch64
  CPU Cores : 4
  Memory : 7950 MB
  Distribution : PynqLinux, based on Ubuntu 22.04
  GLIBC : 2.35
  Model : unknown

XRT
  Version : 2.13.0
  Branch : temp
  Hash : f5505e402c2ca1ffe45eb6d3a9399b23a0dc8776
  Hash Date : 2022-10-21 16:39:50
  ZOCL : 2.13.0, f5505e402c2ca1ffe45eb6d3a9399b23a0dc8776

Devices present
  0 devices found
BDF : Shell Platform UUID Device ID Device Ready*

* Devices that are not ready will have reduced functionality when using XRT tools

```

However, the fact that the PYNQ driver for FINN still works while the C++ one doesn’t puzzles me, and I hoped to have some insight from people more used to PYNQ’s inner workings than I am.

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**Author:** ![marioruiz](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/marioruiz/32/2177_2.png) [@marioruiz](https://discuss.pynq.io/u/marioruiz)\
**Post date:** [June 10, 2025, 1:11pm UTC](https://discuss.pynq.io/t/tysom-3a-zu19eg-pynq-works-but-xrt-doesnt-on-its-own/8534/2 "2025-06-10T13:11:59Z")

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Hi @Mousakaa,

Welcome to the PYNQ community.

Have you tried to run this from inside the Jupyer Lab terminal?

Mario

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<div class="post-metadata">

**Author:** ![Mousakaa](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/mousakaa/32/7090_2.png) [@Mousakaa](https://discuss.pynq.io/u/Mousakaa)\
**Post date:** [June 10, 2025, 1:24pm UTC](https://discuss.pynq.io/t/tysom-3a-zu19eg-pynq-works-but-xrt-doesnt-on-its-own/8534/3 "2025-06-10T13:24:15Z")

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It works. Thank you very much for your time, and I cannot believe I just forgot it needed root permissions.

Arthur

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**Author:** ![system](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/system/32/2_2.png) [@system](https://discuss.pynq.io/u/system)\
**Post date:** [June 13, 2025, 1:24pm UTC](https://discuss.pynq.io/t/tysom-3a-zu19eg-pynq-works-but-xrt-doesnt-on-its-own/8534/4 "2025-06-13T13:24:49Z")

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