ESP8266 Community Forum

Posted: **Thu Dec 01, 2016 3:51 pm**

Hi guys,

I've bought three yellow NodeMcu Dev Boards (VER 0.9, yellow), unfortunately none of them seems to work.

I've flashed the firmware several times (using the latest esptool.py), also with different settings.
Once the flash is completed, I remove the USB cable and then reconnect it.
The blue led starts to blink very very fast and when I try to open the serial port (with baud 115200) I get a bunch of weird characters, e.g.:

Code: Select all

sd$��|�l�<�l�c|����;�clc��gn�dog���c8��lrl;lp�'��lco�<�d�s�ć#��og�l��l �g'l`orǛ�'��d`8�g�r�����b'�|�ld��b��og�$`�gn�los���n{��`p�g�s�����d�cn�|b��og��$`�og�ln{���g��ls��n��d���8�on�$dld�#���`{ll��|�d�|�d�b<����s�cd#��ng�$gn���cp��d{$sd8�o��$b'�|�l�{���c��gn�dćd`�'o$`gs���o��l`p�'�s�ܜ��co�<�dl��c��go�l`�ng�$'{���gs�� x�n�{�����l�cg�|c��gn��l`�g

is there anything else I can try?
Thanks in advance

Posted: **Fri Dec 02, 2016 1:31 am**

I assume you're familiar with http://nodemcu.readthedocs.io/en/latest ... #esptoolpy? Did you set the correct flash mode? Do you have an esptool.py version recent enough to include flash size auto detection? What firmware version do you use?

Posted: **Fri Dec 02, 2016 9:44 am**

marcelstoer wrote:I assume you're familiar with http://nodemcu.readthedocs.io/en/latest ... #esptoolpy? Did you set the correct flash mode? Do you have an esptool.py version recent enough to include flash size auto detection? What firmware version do you use?

Hi, I've flashed the latest firmware (master, default configuration) built on https://nodemcu-build.com using the latest esptool.py

I've also tried different flash mode but nothing changes. I get no error after flashing but I can't use the device with ESPLoader

I've used the same setup with other (more recent...I guess) black NodeMCU boards and everything works out of the box. I guess that the yellow board has something different, here is the model I have: http://www.banggood.com/NodeMcu-Lua-WIF ... 76440.html

Posted: **Sat Dec 03, 2016 8:43 am**

I think I've made some progress...flashing this way:

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esptool.py --port /dev/ttyUSB0 write_flash -fm dio -fs 32m -ff 4m 0x00000 bin/nodemcu_integer_master_20161203-1334.bin  0x3FC000 ~/esp_init_data_default.bin

the blue led doesn't blink anymore and when I open the serial on ESPlorer I get (after 30 seconds!!!):

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Please, reset module or continue.
|s��o�b���n�c���p�l�l�|l�b��oo�lrll�bs|�|lb��plr�bl`p��b�p�oon��n��|loo삞|o��`��
=node.heap()
����c�
=node.heap()
=node.heap()
stdin:1: unexpected symbol near '�'
> 
=node.heap()
=node.heap()
45528

there are some weird characters but it seems to work....until I click "close".
If I try to re-open it doesn't work anymore and I have to flash it again...

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