Okay, thanks, that clears something up… I also missed the part with iodeOS, which is oviosly a custom rom (which I have never heard about before).
This makes your problem a little unique.
So, here a little instruction for affected non-professionals who want want to help finding out whether the phone is dead after the update or only black screened:
Supposed the case you were connected to your home wifi network before the update, should should have been able to see your phone in the router’s network list.
On a Fritz!Box (popular in Germany, but it should work on other routers accordingly) you can log on to you router, check something like “Home Network”, then below “Network”. With your phone switched off it should not appear in the list. When switching on, a good and working phone should connect after booting and you should be able to see it in your “Active connections” list.
Maybe someone with an affected (but not wiped) stock rom FP4 can check if the phone appears in the list after booting…