**** Build of configuration Default for project Sample ESP8266 App ****

make flash 
#/home/xxxx/dev/esp8266/esptool-ck/esptool -cp /dev/ttyUSB0 -bm qio -bz 4M -bf 40 -cd nodemcu -cb 115200 -ca 0x00000 -cf sampleESP8266App_0x00000.bin -ca 0x40000 -cf sampleESP8266App_0x40000.bin
esptool.py --port /dev/ttyUSB0 --baud 115200 write_flash --flash_freq 40m --flash_mode qio --flash_size 4m 0x00000 sampleESP8266App_0x00000.bin 0x40000 sampleESP8266App_0x40000.bin
Connecting...

A fatal error occurred: Failed to connect to ESP8266
make: *** [flash] Error 2

**** Build Finished ****