As I upgraded FB4020 from 19.xx to 21.02 in April, I couldn't configure as I did for 19.xx (vlans and wifi with ssid's). I followed this forum posting
Use SSID in specific VLAN - Wifi connection can not be established - #15 by VLANMaster?
and it worked. I had understood that this instruction was for DSA, and I couldn't do it on my own because 19.xx wasn't DSA. (may be I just didn't remember how I configured 19.xx)
My friend said it's DSA for software switch and "switch" for hardware switch. I expressed it as "not 100% DSA".
So if it's actually not a DSA device at all, this would mean that the updating would be quite easy? The config would be kept, I will just have to install packages again?