Canon EOS 700D hangs on the set

My Canon EOS 700D started to cause problems 2 years ago (see my previous post). It all started with JPEG conversion and Live View / Video modes that worked unreliable.

Now the problem has gotten worse, even RAW shootings will not work. A photo is taken (for example, autofocus and shutter work), but the camera crashes afterwards. Sometimes the screen freezes, sometimes it returns to normal, but the number of remaining images and the red light continue to flash, indicating that the camera is recording the image for ever. When the power is turned off, the camera displays "In the process of saving … remaining images: 1".

Therefore, it seems to be related to saving images. However, even when you take a picture without a memory card, the camera crashes after taking the picture. I tried to reset the camera to the factory default settings and install a magic lantern, but the two did not help. Any ideas on how to diagnose the problem?