ESP8266 Community Forum

Hallo,

I am creating a custum firmware for the ESP8266 under windows using: The DevKit for Windows. Everything compiles fine (and fast). But when I flash the program to the ESP8266 it takes a lot of time around 25 seconds... I think this is normal since I am flashing the entire device again every time.

But is there a way to improve the flashing speed? Maybe by only the parts that are changed or something?

I use the default baud-rate of: 115200

Mydo wrote:... when I flash the program to the ESP8266 it takes a lot of time around 25 seconds... I think this is normal since I am flashing the entire device again every time.

But is there a way to improve the flashing speed? Maybe by only the parts that are changed or something?

25 to 30 sec is about right. As far as I know you can't simply compile and upload small parts because you're uploading full, packed bin file(s) every time, and you can't erase and overwrite the flash memory in very small blocks anyway.

Think of it as free time. Read esp8266.com or hackaday while you're flashing.

Hi Mydo,

Most of the serial flashing time is determined by the serial port speed. 115200bps = 14kilobytes/sec. So a 256kB image will take about 18 seconds just to transfer.

Try running a higher baud rate (230400,460800,691200,921600). Depending on your hardware you'll probably find an upper limit somewhere, all my adapters can manage at least 230400 but only some configurations will work up around 1Mbit.

I'm not sure that I'm correct here ... but since the ESP8266 enters flash mode from a restart, I would imagine that the baud rate expected by the ESP8266 is fixed at 115200 and the partner can only match it. I haven't seen or heard of any feature where we can dynamically choose the baud rate used by the device on boot. If that's the case then we are fixed at 115200.