error while uploading

[huds0nx]

it can't upload it keeps getting an error while uploading.

Log:
Uploading...
esptool v0.4.8 - (c) 2014 Ch. Klippel ck@atelier-klippel.de
setting board to ck
setting baudrate from 115200 to 9600
setting port from /dev/tty.usbserial to /dev/cu.SLAB_USBtoUART
espcomm_upload_file
espcomm_upload_mem
opening port /dev/cu.SLAB_USBtoUART at 9600
tcgetattr
tcsetattr
serial open
opening bootloader
resetting board
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
resetting board
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
resetting board
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
trying to connect
setting character timeout 0
done
setting character timeout 1
done
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
warning: espcomm_sync failed
error: espcomm_open failed
error: espcomm_upload_mem failed

Finished with exit code 255