How to propagate error back to previous layer in CNN?
Since calculating the backward gradients that too in CNN is very math heavy and it's a bit different from normal MLP as in CNN'S we have Tensors not scalar values to multiply so People use Correlation to Calculate the Convolution Operation...


Just adding some links which I refer to from time to time thinking that someday I will be able to do this from scratch (seems impossible with deepening of Layers though...)


Reference 1
Reference 2
CS231N Slides (Lecture 4-6 specially, the computational graphs construction are very helpful to understand the Back-propagation Algorithm..)


It would be great if Someone can transfer the Equations into Latex here
So that the question can be answered formally..

Based on the above Links, here's what I got,(Came to know that Convolutions are equivalent to Correlation)

Image 1

Image 2

Stack doesn't allow me uploading image so using gdrive..(do rotate one of the images, the first one actually)

Hope it will give you an idea...