ESP does not boot if Rx not HIGH

[klemen-skoda]

Hi,

I've been testing serial communication between ESP 12F and another device.
What i've found is if Rx pin of ESP 12F has to be HIGH at boot. If it is pulled LOW before power is applied ESP does not boot.
In my case Arduino nano had LED on pin 13 which i used for software serial and was pulling the pin to ground.

Just posted because i haven't found anything anywhere about Rx pin having to be HIGH at boot for ESP to start up.