As was noted in recent messages on the list, recent Debian builds (e.g. #118, #124) has WiFi working. However, I had troubles connecting to my Internet access point, with wpa_supplicant (or kernel while running it) throwing timeout errors waiting for AP authentication response.
After fiddling with it, I remembered that the AP is 802.11g, grabbed a 802.11n mobile router, and the HiKey connected to it without issues.
I tried to play with few seemingly related wpa_supplication config params, but nothing had an effect (btw, it's a bit of chore, because on stop, wpa_supplicant brings wlan0 down, and it's broken after that, not up'able again; "reboot" doesn't work, and there's no hardware reset button, so disconnecting power jack is the only choice). So, I figure the problem is in driver. I'm currently reading TI's docs on WL1835MOD (http://processors.wiki.ti.com/index.php/WL18xx) to see if there's anything related, but if someone may have any hints, that would be appreciated.