Atmega328p reset not working
When ZM5202 programming:
  AVR Reset -> gnd;
  ZM5202 Reset -> programmer reset;
  CS -> high;
  Result: NOK


No surprises here: The AVR turns on its ISP interface in Reset and drives one of the SPI lines, preventing the ZM5202 from doing the same. 

It would also try to read the data as ISP commands, so you could end up with erased or modified memory on the AVR by accident.


  AVR Reset -> floating


The AVR has a weak internal pullup on its reset pin. This means floating => not in Reset.