Review on 4pcs MakerFocus ESP8266 ESP-01 WiFi Transceiver Receiver Module with 1MB SPI Flash, DC3.0-3.6V IoT WiFi Module Board, Compatible with Arduino by Robert Moloney

First I tried the ESP-01 firmware scheme I've used in the past and none of them went into AT command mode. I saw DONE but couldn't go beyond it. I tried to use an Arduino UNO as a programmer. The terminal session started as expected in AT command mode and worked fine. Then I tried flashing the example program to blink. It seemed to work, but when it was done the ESP module didn't blink and it stopped processing AT commands. updated 14.05. The seller immediately sent 4 replacements. For some reason they all worked with the same flash setting. I don't know what could be the problem, but thanks to the quick response of the sellers everything is fine now.