iPod nano gen3 software problem

My ipod nano gen 3 doesn't load his operating system. I thought it was because of low charge but when i charged him nothing happened. It is my old ipod and it is important for me as memory. I wanted to recover him but i used apple mac and i connected ipod to finder and after "preparing" mac said that software is unavailable. I used other windows computer and i get error 1675 from itunes, problem with communication. I opened back cover because i thought that maybe sething happened inside. Also i cannot access to files on my ipod from computer. I bought new cable and it haven't change nothing also i cannot Boot it because it only react to main and select button to restart. I wanted to download Rockbox software but i cannot access my ipod from computer to load software. I have a suspicion that this is because of problem with NAND flesh memory chip. I want to change this chip, but i have read that i need to program my new chip before replacing but i have no idea how to do it. Can you help me to solve this problem? I would be grateful to you all