I've run into some issues with the new Pi zero W. First I tried to run an image of raspbian from 11-1-17' but that did nothing. Well, it booted but couldn't set up a Wi-Fi network. So I've installed a new image 16-2-17' and then the Wi-Fi worked like I expected.

Later, I updated a Pi 2 and swapped that SD card into the Pi zero W, and everything was working fine.

Then I changed the GPIO ports in some python programming and I got all sorts of errors (and again no Wi-Fi).

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 guess is that the onboard Wi-Fi 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 Wi-Fi.

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 is, how to use the UART/TTY with Bluetooth/Wi-Fi on a PI zero w?

UPDATE2: I tried to disable Bluetooth using the /boot/config.txt adding dtoverlay=pi3-disable-bt but with no success. Bluetooth still gets loaded.