FireMotD has nothing to do with dhcpcd. I suggest to stop guessing around and arbitrarily try things.
dhcpcd crashing is probably the effect of network problems not the cause.
Duh! That now is not a supported setup of openHABian.
You should have told us about right in your first post.
So either move to a supported setup (Ethernet or Wi-Fi) or don’t ask for help on your system, please.