Hi Polskifacet,
It should work absolutely fine. I’m wondering what you mean though by a regular ESP-12f board. A standalone ESP12f module itself needs external pull-up/pull-down resistors on certain pins to boot. As you’ve mentioned the flashing wifi LED, I’m guessing you have a board with the esp module soldered on and all of the supporting passive components already in place, along with the led attached to a gpio pin. So… My guess is perhaps the gpio pins in use on the board may be in the wrong state at boot, or something connected to the pins is holding it in that state. (I’m assuming you’ve checked to see if it’s presenting a Wifi AP whilst it’s LED is flashing?) Do you have a web link to the board and are there any jumpers, or anything connected to the pins?