I've ran into some issues with the new Pi zero W.
 first i tryed to run an image of raspbian from 11-1-17' but that did nothing, well it booted but couldn't setup a wifi network.
so i've installed a new image 16-2-17' and than the wifi worked like i suspected.

Later i've updated a Pi 3 and swoped that sd card into the Pi zero W, everything was working fine.
Than i changed the GPIO ports in some python programming and i got all sorts of errors (and again no wifi).    
    
    brcmfmac: brcmf_sdio_txfail: sdio error, abort command and terminate frame
    brcmfmac: brcmf_sdiod_regrw_helper: failed to read data F1@0x0a020, err: -84
    brcmfmac: brcmf_sdio_isr: failed backplane access

my first gues is that the onboard wifi is connected with the TTY GPIO?
as i'm using it to read from a dutch smart meter (DSMR4.x) looks like i've got a conflict with the wifi.

UPDATE:

hunch was correct in the system log:    
    
    btuart[431]: Set Controller UART speed to 3000000 bit/s
    Device setup complete
    Started Configure Bluetooth Modems connected by UART.

so now the question, how to use the UART/TTY with bluetooth/wifi on a PI zero w?