...
Then, if I try a pkgadd with the new A3ME on top of 9S5K + 9Z5N, I get:
INSTALL ERROR: This core OMNI-A3ME Signalware packages requires Service Pack 5 ECN Base package S5N or later installed in this instance.
Solution: in /etc/swinstall/dat/swadmin:
ECNCHECK=DISABLED