title: Illegal instruction(core dumped) error on Jetson Nano
body: <p>Sorry if my description is long and boring but I want to give you most important details to solve my problem.
  Recently I bought a Jetson Nano Developer Kit with 4Gb of RAM, finally!, and in order to get, which I consider, the best configuration for object detection I am following this guide made by Adrian Rosebrock from Pyimagesearch:</p>
  <p><a href="https://www.pyimagesearch.com/2020/03/25/how-to-configure-your-nvidia-jetson-nano-for-computer-vision-and-deep-learning/" rel="noreferrer">https://www.pyimagesearch.com/2020/03/25/how-to-configure-your-nvidia-jetson-nano-for-computer-vision-and-deep-learning/</a> Date:March, 2020.
  A summary of this guide is the following:</p>
  <ul>
  <li>1: Flash Jetson Pack 4.2 .img inside a microSD for Jetson Nano(mine is 32GB 'A' Class)</li>
  <li>2: Once inserted on the Nano board, configure Ubuntu 18.04 and get rid of Libreoffice entirely to get more available space</li>
  <li>3: Step #5: Install system-level dependencies( Including cmake, python3, and nano editor)</li>
  <li>4: Update CMake (without any errors)</li>
  <li>5: Install OpenCV system-level dependencies and other development dependencies</li>
  <li>6: Set up Python virtual environments on your Jetson Nano( succesfully installed virtualenv and virtualenvwrapper without errors including the bash file edition with nano)</li>
  <li>7: Create virtaul env with python 3 and install protobuf and libprotobuf to get an more efficient Tensorflow. Succesfully installed. It took an hour to finish, that's normal</li>
  <li>8: Here comes the headbreaker: install numpy and cython inside this env and check it importing numpy library
  When I try to do this step I get:
  Illegal instruction(core dumped) as you can see in the image:
  [Error with Python3.6.9]: <a href="https://i.stack.imgur.com/rAZhm.png" rel="noreferrer">https://i.stack.imgur.com/rAZhm.png</a></li>
  </ul>
  <p>I said, well let's continue with this tutorial anyway:</p>
  <ul>
  <li>9: Install Scipy v1.3.3: everything is ok with first three lines, but when I have to use python to execute the stup.py file, IT shows up again(not the clown).
  [Can't execute this line either]: <a href="https://i.stack.imgur.com/wFmnt.jpg" rel="noreferrer">https://i.stack.imgur.com/wFmnt.jpg</a></li>
  </ul>
  <p>Then I ran an experiment, I have created this &quot;p2cv4&quot; env with Python 2, installed numpy and tested it:
  [With Python 2]: <a href="https://i.stack.imgur.com/zCWif.png" rel="noreferrer">https://i.stack.imgur.com/zCWif.png</a></p>
  <p>I can exit() whenever I want and execute other lines that use python
  So I concluded that is a python version issue. When I want to execute any python code, terminal ends the program with core dumping, apt-get or pip DO NOT show any errors. And I want to use python 3 because someday in the future a package or library will require python 3.</p>
  <p>For python 3 last version for the Jetson Nano is 3.6.9, and idk which version was currently active in March, 2020, like the one Adrian used at that time</p>
  <p>In other posts I read that this SIGILL appears when a package or library version like Numpy of TF is not friendly anymore with a specific old or low power CPU, like in this posts:
  <a href="https://stackoverflow.com/questions/49327879/illegal-hardware-instruction-when-trying-to-import-tensorflow">Illegal hardware instruction when trying to import tensorflow</a>, <a href="https://github.com/numpy/numpy/issues/9532" rel="noreferrer">https://github.com/numpy/numpy/issues/9532</a></p>
  <p>So I want to downgrade to a older python version like 3.6.5 or 3.5 but I can't find clear steps to do so in Ubuntu. I thinks this will fix this error and let me continue with configurations on the Jetson Nano.</p>
  <p>The pyimageseach guide uses Python 3.6 but it do not specifies if is last 3.6.9 or another. If is not python causing this error let me know. HELP please!</p>