YOLO and SSD are based on Nvidia's proprietary CUDA technology which is not available on Raspberry simply because of the GPU vendor is not Nvidia.
Even more, there seems to be no implementation of even OpenCL for the Raspberry's GPU.
What you can do is to try port YOLO's of SSD's CNN core from CUDA to Raspberry GPU's assembler, in the way described in, ...
After a lot of browsing online for answers to these questions, this is what I came up with.
What are the initial layers in this case? How exactly can I freeze them?
The initial few layers are said to extract the most general features of any kind of image, like edges or corners of objects. So, I guess it actually would depend on the kind of backbone ...