Flash Tool 3.4.9.2 - fails with Invalid Packet Head

[trkraghu]

This is a ESP8266-12E on a ESP 13 Shield. Mounted on a UNO - but right now the Arduino UNO is just providing 5V power. No communication with it

Trying to burn

the original AT Firmware V2.0.1 ( the latest on to the chip ) Using the Original; Espressif flasher tool Version 3.4.9.2 on a Windows 10 PC.

I have no problem connecting up to the chip, start downloading but then for some mysterious reason the operation fails at random at some point with a message "Invalid head of packet('') "

Attaching the screen shot. Any idea what is going wrong - the firmware , flasher - all are the latest. And yet this woe. Is something broke ??