ESP8266 Community Forum

Hi all,

I write you only to give some light about errors during flashing with esptool and other tools (ESP8266Flasher.exe, flash_download_tool_v1.2_150512.exe, etc).

If you are trying to flash the ESP8266 (ESP12 module for example) and your flashing operation hangs in the middle of the procedure, pay attention to this. It can save you a lot of time...

Depending on which USB to TTL converter you are using, the system might not work correctly. There must be something about buffering or drivers or something in windows that makes a strong difference whether you are using one converter or another.

Validated USB to TTL (these are known to work)
- TTL-232R-3V3-PCB from FTDI
- Silicon Labs CP210x USB to UART bridges

Known that does not work:
- Prolific based USB to TTL converters

If you have a Prolific USB to UART bridge, you might try to make it work by changing the esptool.py by reducing the packet size of the flash transmission
ESP_RAM_BLOCK = 0x180
ESP_FLASH_BLOCK = 0x40

Kind regards,

Juan Ramón Vadillo

jvadillo wrote:Known that does not work:
- Prolific based USB to TTL converters

This is maybe Windows driver related, because I'm personally using a Prolific USB with ESP under Linux for more than a year.

Yes, this problem happens in windows.

I have no idea about what is the situation in linux.

There are some people having the same problem and I decided to write about it:
http://www.esp8266.com/viewtopic.php?f=6&t=2791

I do know there is "something" with clones and drivers that try to destroy them when they recognise them.