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ESP8266 shows garbage in serial monitor

I have my ESP8266 connected via serial to USB like the image shows: enter image description here

It worked just fine, however, when I tried flashing Blynk code

#define BLYNK_PRINT Serial 
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
char auth[] = "YourAuthToken";
void setup()
{
 Serial.begin(9600);
 Blynk.begin(auth, "ssid", "pass");
}
void loop()
{
 Blynk.run();
}

It started outputting loads of garbage in the serial monitor, while Blynk app said ESP is not connected to network. I've tried since then flashing empty sketches or some other stuff, whatever I do, serial monitor shows loads of junk. I've tried changing modes, I've tried changing baud rates (57600 was default, and AT worked just fine).

Junk example:

 ...ÕZaP‚,JHVYo—¡VÕ]J*ÉW\¡Õ\Õ-"aUŠQd®"¡âJ%H
!HiZÊIIRPÖuUPÒ‚BñZT\ *EUeZB\)*EVjU!\©Š_\¢"ÅVaqYiUμP"¬ÕPQT°*uH)HZKB*ÕXauH!HBHBH...μEIâHBH!H©aqY+hZVB\BH!HÊ*Òμe�qHBHBHŠ*i±...Z¦-hUμPÔ¬ÔPQT°*uH)H-KB*ÕXauH!HBHBH...μEB\!H!HBVaqY+iZVB\BH!HeVÒZ¢qHBHBHŠ*iQ...Z¦-hUμPÔ¬ÔPQTaYRB\ jHiBHaaYRB\BH!HBVaaYRB\BH!HBVaqY+iZVB\BH!HÊVÒZ¢qHBHBHŠ*i±Õ\V
iUμPÔ¬ÕPQT°*uH)H-JBVaaYRB\BH!H!VaaYR!\BHBH!Vaq©+hZW!\BHBHJ*iμE�âHBH!HŠ*i±...Z¦-hUμPÕ¬ÔPQTaYR!\ %Hi!HÕXauH!HBHBH...μEIqHBHBH

Answer*

This might be related to old ESP-01 firmware. I mean 2018-ish firmware in 01s I bought 3 years ago or so.

I had the same problem –- `write_flash` works but after the reset garbage is coming in. Try this [installs micropython; change serial device to fit your setup]:

 esptool.py -p /dev/tty.usbserial-02022FD3 erase_flash
 esptool.py -p /dev/tty.usbserial-02022FD3 write_flash 0xfc000 esp_init_data_default.bin
 esptool.py -p /dev/tty.usbserial-02022FD3 write_flash -fs 1MB 0x00000 ../upython-esp8266-1m-20220117-v1.18.bin

Note: the location is flash size dependant – my ESP-01s have 1 MB of flash and you can check it using the `esptool.py flash_id` command. Use this reference:

 - `0x7c000` for 512 KB, modules like most ESP-01, -03, -07 etc. 
 - `0xfc000` for 1 MB, modules like ESP8285, PSF-A85, some ESP-01, -03 etc.
 - `0x1fc000` for 2 MB
 - `0x3fc000` for 4 MB, modules like ESP-12E, NodeMCU devkit 1.0, WeMos D1 mini

The `esp_init_data_default.bin` file is taken from **Espressif SDK**, here's my SHA256 of it:

 shasum -a 256 esp_init_data_default.bin
 81e04e5ec0afef0aad3b52cca2a9bbccc205f4c57334c438e1d81e38ce94b932 esp_init_data_default.bin

But I guess the init file from Github should work OK as well [didn't try though]. 

https://github.com/espressif/ESP8266_RTOS_SDK

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