I have a 3220.
It looks like you cannot force HA1 onto the dataplane interfaces (you can for HA2) on the larger firewalls.
I tried making eth1/18 (fiber) an HA interface, but it would not let me select the interface in the HA1 config (it was an option for HA2). Same behavior on a 5200 series.
I know there are sometimes behind the curtains things that can be done, but wanted to check here to see if I was SOL or if there is something I am missing.
Looks like you're right, the larger (x2xx) platforms can't do dataplane HA1, probably because they have a bunch of dedicated interfaces
Either I'm doing something wrong, or it isn't working.
I enabled 1/18 as HA interface type.
I can choose it for HA2, but not HA1
You need to set the interface to type HA first, before you try to add it as a HA1 interface. Also make sure it is not assigned to another HA (1 backup, 2,...) already