G1 cannot flash latest firmware

[Bodad]

Hi.  My G1 isn't connecting to the mobile network.  This happens regularly.  A simple reboot sometimes corrects this but ultimately, a firmware flash is the only way to reinstate mobile connectivity.  However, when I try to re-flash the G1 with KCS_G1_V3.19.1.bin, the flash    
interface starts the erase process but when the installation process starts, it report that the device has been reset to firmware mode?
   

I'm using Tasmota web installer to flash.  It has always worked before.  How can I re-flash the G1?

Thanks in anticipation.