# Error no device found when loading overlay **URL:** \ **Category:** Support\ **Created:** [September 5, 2021, 3:09pm UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989 "2021-09-05T15:09:38Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Poly\_Morph](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/poly_morph/32/2345_2.png) [@Poly\_Morph](https://discuss.pynq.io/u/Poly_Morph)\ **Post date:** [September 5, 2021, 3:09pm UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/1 "2021-09-05T15:09:38Z")
I am following the step of from [Overlay Tutorial — Python productivity for Zynq (Pynq) v1.0](https://pynq.readthedocs.io/en/v2.0/overlay_design_methodology/overlay_tutorial.html) Currently I’m using Jupyter Notebook on the Ultra96 v2 through ssh tunnel and I encountered the following error when trying to load the overlay. ```auto --------------------------------------------------------------------------- RuntimeError Traceback (most recent call last) in () 1 from pynq import Overlay ----> 2 ol = Overlay('/home/xilinx/pynq/overlays/adder/adder.bit') /usr/local/lib/python3.6/dist-packages/pynq/overlay.py in __init__ (self, bitfile_name, dtbo, download, ignore_version, device) 335 336 """ --> 337 super(). __init__ (bitfile_name, dtbo, partial=False, device=device) 338 339 self._register_drivers() /usr/local/lib/python3.6/dist-packages/pynq/bitstream.py in __init__ (self, bitfile_name, dtbo, partial, device) 109 if device is None: 110 from .pl_server.device import Device --> 111 device = Device.active_device 112 self.device = device 113 /usr/local/lib/python3.6/dist-packages/pynq/pl_server/device.py in active_device(cls) 94 if not hasattr(cls, '_active_device'): 95 if len(cls.devices) == 0: ---> 96 raise RuntimeError("No Devices Found") 97 cls._active_device = cls.devices[0] 98 return cls._active_device RuntimeError: No Devices Found ``` Does anyone know how do I fix this? ---
**Author:** ![PeterOgden](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/peterogden/32/55_2.png) [@PeterOgden](https://discuss.pynq.io/u/PeterOgden)\ **Post date:** [September 6, 2021, 8:27am UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/2 "2021-09-06T08:27:36Z")
This error is usually a result of `/dev/xlnk` not existing. Can you check if the device is there? What image are you running? Peter ---
**Author:** ![haroic2021](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/haroic2021/32/2349_2.png) [@haroic2021](https://discuss.pynq.io/u/haroic2021)\ **Post date:** [September 7, 2021, 3:54pm UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/3 "2021-09-07T15:54:17Z")
Hi peter, I am facing the same issue as well, I have check and dev/xink is there, how do I proceed? ![image](https://us1.discourse-cdn.com/flex019/uploads/pynq1/original/2X/a/a4add825c5c5215504f25a47831d7b1f2b12f01c.png) ---
**Author:** ![thepipa](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/thepipa/32/2444_2.png) [@thepipa](https://discuss.pynq.io/u/thepipa)\ **Post date:** [October 11, 2021, 4:27pm UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/4 "2021-10-11T16:27:18Z")
Hello. Im having the same issue on my Zybo using pynq 2.6 as base. ```auto from pynq.overlays.base import BaseOverlay ol = BaseOverlay("base.bit") RuntimeError: No Devices Found ``` ```auto xilinx@pynq:~$ ls /dev/xlnk ls: cannot access '/dev/xlnk': No such file or directory xilinx@pynq:~$ ls /sys/class/fpga_manager/ ls: cannot access '/sys/class/fpga_manager/': No such file or directory ``` Any ideas @PeterOgden ? I used [this files](https://github.com/altuSemi/PYNQ4Zybo) (kernel) to the boot partition of the sd. The board appears to boot correctly but cant load any bitfile. Some extra info, not sure if relevant: ```auto xilinx@pynq:~$ sudo systemctl start xilinx-apf-driver.service [sudo] password for xilinx: Job for xilinx-apf-driver.service failed because the control process exited with error code. See "systemctl status xilinx-apf-driver.service" and "journalctl -xe" for details. xilinx@pynq:~$ systemctl status xilinx-apf-driver.service ● xilinx-apf-driver.service - Xilinx APF Driver Service. Loaded: loaded (/etc/systemd/system/xilinx-apf-driver.service; disabled; vendor preset: enabled) Active: failed (Result: exit-code) since Mon 2021-10-11 22:37:24 UTC; 7s ago Process: 1632 ExecStart=/sbin/modprobe xlnk-eng (code=exited, status=1/FAILURE) Main PID: 1632 (code=exited, status=1/FAILURE) xilinx@pynq:~$ sudo depmod depmod: ERROR: could not open directory /lib/modules/3.17.0-xilinx-dirty: No such file or directory depmod: FATAL: could not search modules: No such file or directory ``` ---
**Author:** ![Roua\_Zaied](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/roua_zaied/32/2863_2.png) [@Roua\_Zaied](https://discuss.pynq.io/u/Roua_Zaied)\ **Post date:** [February 18, 2022, 9:09am UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/5 "2022-02-18T09:09:54Z")
* * * RuntimeError Traceback (most recent call last) in () 1 from pynq.overlays.base import BaseOverlay ----\> 2 base = BaseOverlay(“base.bit”) /usr/local/lib/python3.6/dist-packages/pynq/overlays/base/base.py in **init** (self, bitfile, \*\*kwargs) 84 85 def **init** (self, bitfile, \*\*kwargs): —\> 86 super(). **init** (bitfile, \*\*kwargs) 87 if self.is\_loaded(): 88 self.iop\_pmoda.mbtype = “Pmod” /usr/local/lib/python3.6/dist-packages/pynq/overlay.py in **init** (self, bitfile\_name, dtbo, download, ignore\_version, device) 334 335 “”" → 336 super(). **init** (bitfile\_name, dtbo, partial=False, device=device) 337 338 self.\_register\_drivers() /usr/local/lib/python3.6/dist-packages/pynq/bitstream.py in **init** (self, bitfile\_name, dtbo, partial, device) 109 if device is None: 110 from .pl\_server.device import Device → 111 device = Device.active\_device 112 self.device = device 113 /usr/local/lib/python3.6/dist-packages/pynq/pl\_server/device.py in active\_device(cls) 92 if not hasattr(cls, ‘\_active\_device’): 93 if len(cls.devices) == 0: —\> 94 raise RuntimeError(“No Devices Found”) 95 cls.\_active\_device = cls.devices[0] 96 return cls.\_active\_device RuntimeError: No Devices Found the same 🤒 ! ---
**Author:** ![haipnh](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/haipnh/32/4439_2.png) [@haipnh](https://discuss.pynq.io/u/haipnh)\ **Post date:** [June 27, 2022, 9:18am UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/6 "2022-06-27T09:18:51Z")
I have the same problem. I logged in via SSH to my PYNQ-ZU board. Then ran ```nohighlight sudo -s source /etc/profile.d/pynq_venv.sh python3 ``` In Python prompt, I ran some lines of code and get the following error: ```python >>> from pynq.overlays.base import BaseOverlay >>> from pynq.lib.video import * >>> base = BaseOverlay("base.bit") Traceback (most recent call last): File "", line 1, in File "/home/xilinx/pynq/overlays/base/base.py", line 48, in __init__ super(). __init__ (*args, **kwargs) File "/home/xilinx/pynq/overlay.py", line 336, in __init__ super(). __init__ (bitfile_name, dtbo, partial=False, device=device) File "/home/xilinx/pynq/bitstream.py", line 111, in __init__ device = Device.active_device File "/home/xilinx/pynq/pl_server/device.py", line 94, in active_device raise RuntimeError("No Devices Found") RuntimeError: No Devices Found ``` ---
**Author:** ![skalade](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/skalade/32/686_2.png) [@skalade](https://discuss.pynq.io/u/skalade)\ **Post date:** [June 27, 2022, 10:38am UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/7 "2022-06-27T10:38:41Z")
Hi there, Looks like this is happening because when you login as root you enter a new environment, and lose the XILINX\_XRT environment variable. This is usually set by calling xrt\_setup.sh on startup along with pynq\_venv.sh in /etc/profile.d/, which is why we don’t see these errors in jupyter lab. Running ```auto export XILINX_XRT=/usr ``` before your python call should resolve this. Thanks Shawn ---
**Author:** ![haipnh](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/haipnh/32/4439_2.png) [@haipnh](https://discuss.pynq.io/u/haipnh)\ **Post date:** [June 27, 2022, 11:04am UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/8 "2022-06-27T11:04:02Z")
Thank you for spotting the problem. It can work in the terminal now. If I don’t change to root user, it will print out the following error message when loading a bitstream. ```auto >>> base = BaseOverlay("base.bit") Traceback (most recent call last): File "", line 1, in File "/home/xilinx/pynq/overlays/base/base.py", line 48, in __init__ super(). __init__ (*args, **kwargs) File "/home/xilinx/pynq/overlay.py", line 354, in __init__ self.download() File "/home/xilinx/pynq/overlays/base/base.py", line 91, in download super().download() File "/home/xilinx/pynq/overlay.py", line 416, in download Clocks.set_pl_clk(i, div0, div1) File "/home/xilinx/pynq/ps.py", line 331, in set_pl_clk cls._instance.set_pl_clk(clk_idx, div0, div1, clk_mhz) File "/home/xilinx/pynq/ps.py", line 339, in _instance cls._real_instance = _ClocksUltrascale() File "/home/xilinx/pynq/ps.py", line 491, in __init__ self._crf_mmio = MMIO(self.CRF_APB_ADDRESS, 0x100) File "/home/xilinx/pynq/mmio.py", line 100, in __init__ self.array = self.device.mmap(base_addr, length) File "/home/xilinx/pynq/pl_server/embedded_device.py", line 527, in mmap raise EnvironmentError('Root permissions required.') OSError: Root permissions required. ``` ---
**Author:** ![skalade](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/skalade/32/686_2.png) [@skalade](https://discuss.pynq.io/u/skalade)\ **Post date:** [June 27, 2022, 12:04pm UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/9 "2022-06-27T12:04:15Z")
Unfortunately that’s expected behavior! We run everything on pynq as root – you’ll notice that the jupyter terminal is the root user by default. PYNQ touches a lot of devices and memories that require elevated privileges. There’s a nice [explanation](https://discuss.pynq.io/t/pynq-overlay-without-root-privileges/212) by Peter from a while back on why pynq works this way. Thanks Shawn ---
**Author:** ![haipnh](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/haipnh/32/4439_2.png) [@haipnh](https://discuss.pynq.io/u/haipnh)\ **Post date:** [June 27, 2022, 1:18pm UTC](https://discuss.pynq.io/t/error-no-device-found-when-loading-overlay/2989/10 "2022-06-27T13:18:48Z")
I got it and appreciate that. Hai