使用 NodeMCU-PyFlasher.exe 和 flash_download_tool_3.9.2.exe 烧录均成功，但是AT没反应。
下面是 NodeMCU-PyFlasher.exe 的日志
Command: esptool.py --port COM3 --baud 115200 --after no_reset write_flash --flash_size detect --flash_mode dio 0x00000 E:\AWS\aithinker\ESP8266-IDF-AT_V2.2.1.0\ESP8266-AT-V2.2.1.0\factory\factory_WROOM-02.bin --erase-all
esptool.py v3.0
Serial port COM3
Connec
ting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: 40:f5:20:2c:62:7b
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Auto-detected Flash size: 4MB
Erasing flash (this may take a while)...
Chip erase completed successfully in 8.9s
Flash params set to 0x024f
Compressed 2097152 bytes to 546983...
Wrote 2097152 bytes (546983 compressed) at 0x00000000 in 48.8 seconds (effective 343.8 kbit/s)...
Hash of data verified.
Leaving...
Staying in bootloader.
Firmware successfully flashed. Unplug/replug or reset device
to switch back to normal boot mode.
换烧录阿里云这个固件AT正常：
NodeMcu-AT-1\Ai-Thinker_ESP8266_DOUT_AiCloud_v0.0.0.6_20170517\firmware\Ai-Thinker_ESP8266_DOUT_32Mbit_AiCloud_0.0.0.6_20170517.bin
