ESP8266 Community Forum

- Wed Mar 17, 2021 7:56 am #90863 You are obviously viewing the boot messages at 74480 baud. What speed are you trying to upload at? Have you tried 115200 as the chip will normally switch to this during boot?

Although GPIO2 needs to be high to get into the right start up mode it does have a weak pull up during boot which is normally sufficient assuming the pin is not connected to anything else. Obviously it is worth trying an external pull up to eliminate this as a cause.

- Wed Mar 17, 2021 8:46 pm #90874 Hi btideyn The upload speed is 115200.
I finally found the problem, in fact there was a short circuit between MISO and IO9 ( it was made by unmelt solder paste underneath the esp board) because of that the esp was not able to reach the memory where the sdk was stored, and so not able to receive a firmware.

The key about that is the boot mode code, a normal start from reset will give you (3,6) and a reset with IO0 LOW will give you (1,6).

IF you do not have 1 or 3 then you have an issue with IO0, IO15 or IO2. If you don't have 6, maybe you have a issue with the esp memory connected on the SPI of the esp.

I found all informations about boot code here:
https://riktronics.wordpress.com/2017/1 ... explained/

Thank you all who took time to read and help me!