I bought 3 pcs of esp-12 from http://www.banggood.com/Geekcreit-Doit-NodeMcu-Lua-ESP8266-ESP-12E-WIFI-Development-Board-p-985891.html and the first one I'm testing shows the same issue as described in the initial post.
Also, these have GPIO6 label where the GPIO0 should be, see attached img.
When checking the serial console at 76800 , this is what I get (setup done as described in the first post):
GPIO0 -> GND : ets Jan 8 2013,rst cause:2, boot mode:(1,6)
GPIO0 -> floating or to VCC with 10k: ets Jan 8 2013,rst cause:2, boot mode:(3,6)
According to what I found on some other page, the GPIO0 appears to be pulled down fine, also all other pin voltages look ok:
1: normal boot
2: reset pin
3: software reset
4: watchdog reset
Anyone figured out any solution for this, or it's just a bad batch .... again.