Filesystem load to RAM vs piping

I had hoped I'd managed to convert the instructions myself, but no luck.

Here's what I had

digitalWrite(A14,1);
digitalWrite(A13,0);
digitalWrite(A15,0);
digitalWrite(A15,1);

Serial2.setup(115200, { rx: A3, tx : A2 });
Serial2.on('data', function(d) { USB.write(d); });
USB.on('data', function(d) { Serial2.write(d); });
Serial1.setConsole();

but when I run esptool.py I just get:

esptool.py v1.3
Connecting....
Auto-detected Flash size: 32m
Running Cesanta flasher stub...

A fatal error occurred: Invalid head of packet (b'\x13')