Review on 📡 Izokee ESP-01 Serial WiFi Transceiver Module with USB Converter, Compatible with Arduino by James Holker

Includes universal USB to ESP-01 flash driver and ESP-01 module. However, I had a problem with the ESP8266 ESP-01 module. It is programmed without errors, but the program never runs. I've tried other USB adapters, checked GPIO0, flashed the original AT firmware, etc. Every time the module got a software/firmware update but still wouldn't boot. Finally connect it with a serial monitor (Termite) at 78400 baud to read the boot messages. This is where I noticed that it loaded, but with a checksum error. This led to the decision that you need to program this with the DOUT flash mode. It doesn't work with DIO like all my other ESP8266 modules. If you are using the Arduino IDE to program, go to Tools, Flash Mode: and select DOUT. This small change worked like a charm. Apparently different memory chips are used and this manufacturer used a memory chip that only supports the DOUT method.