I'm trying to use pi3d in my Nanopi m4v2. However, after installing pi3d and running a test script from [the demos ][https://github.com/pi3d/pi3d_demos], I get an AttributeError: 'DisplayOpenGL' object has no attribute 'context'.

In RaspberryPi, we need to configure the gpu_mem in /boot/config.txt. How can I set the gpu_mem since the /boot/ folder is empty.