I edited the serial number in the XPEnoboot iso. The file I edited is "isolinux.cfg", still can't get HA to work. Since I used ESX, I modified the MAC addresses of the all interfaces in ESX. The MAC range for Synology starts with 00:11:32.
I get all the way to "confirm settings" and then click apply. After a minute or two, I get "Operation failed. Please re-login and try again."