your suggestion make sense but in my demo environment I had problem about cluster ports.
In demo env, I upgraded from fas8020 to fas2552(no internal drive) but one controller completing without problem. After ı select options 6 ( Update flash from backup config), I modify new cluster ports and then migrate cluster lif to new cluster port with no problem. But in second node ı also modied cluster port but when I checked lifs, output just show management lif. I tried to use migrate but it gave error.
After some diggig ı found another solution. before I halt second old node, modfiying cluster port which exists on new node. After then when I attached the cable and boot new node, it is opening with that config and has no problem to connect cluster.
At the end why ı want to use ha interconnect(e0a and e0b) in Fas8300 for cluster port, because it is same cluster port in fas8020(e0a and e0b).