I too was having this issue, but found an answer from another post on this forum by mr Morse.
Navigate to your esptool.py file and open it up with your editor ( I used vim, as I am using the terminal on my Mac).
you will see 2 lines
Line 43 ESP RAM BLOCK =0x1800 //change this to 180
Line 44 ESP RAM BLOCK =0x400 //change this to 40
save the file, and try again.
This worked for me today. Spent hours trying to get it to work, edited the file as described and presto, first time.
Hope this helps...