Romming problem(setup wizard prompts me to update)

unlocked htc one m8
I'm unlocked rooted and s off, when I try to flash a rom with twrp(latest) ,(doppelkanger gpe and skydragon gpe) everything goes fine so boot into the phone and the setup wizard for the rom starts.
I thought cool it works, then in the setup wizard it prompts me to do a system update(which i cant skip) of 620mb, of course the system update doesnt work cause i have a non stock recovery.
Can't do anything about it...