user61727: Well hello, experts,
I've been trying to fix my issue all time, but all in vain.
I have an Esp8266-01 with 1MB memory. I've flashed it with an official AT firmware V2.0.0 of espressif with the help of this tutorial-arduino as a usb/TTL-: "https://www.allaboutcircuits.com/projects/flashing-the-ESP-01-firmware-to-SDK-v2.0.0-is-easier-now/", and it was a successful flash.
However, when trying to send AT commands in the serial monitor at different baud rates nothing happens.
I'll provide you with all the information down here:

Schematic for both flash and normal mode:



I used the official flasher tool from espressif
I used both Arduino IDE and Termite with no results
I've uploaded the blink sketch successfully into my module, but it never runs and blinks.
After lots of tries and resets I started to receive some information:


But still no answers from this module!!!
Could you help me, please?

user37622: The tutorial is to flash SDK 2.0 AT firmware. The AT 2.0.0 firmware is build with RTOS SDK. The 2.0 AT firmware available on Espressif site was build with settings not compatible with esp-01. It is built for 2 MB flash and  communicates over pins 13 and 15.
The latest NonOS SDK AT firmware is 1.7.1 (SDK 3), but it requires 2 MB flash too. It is possible to flash it to 1 MB module with the 2MB-c1 parameter with esptool.py. (The OTA update command will not work.)
GitHub user loboris (Boris Lovosevic) builds customized versions of AT firmware with SDK 3 for all flash sizes. You can download the files from his ESP8266_AT_LoBo GitHub repository. If you can't run his flash.sh utility, then for 1 MB flash you can Flash Download Tool with bin/upgrade/esp8266_AT_1_2.bin file and the right addresses for 1 MB flash: boot_v1.7.bin on 0x0; esp8266_AT_1_2.bin on 0x01000; esp_init_data_default.bin on 0xfc000 and blank.bin on 0x7e000 and 0xfe000.

61727: <p>Well hello, experts,
I've been trying to fix my issue all time, but all in vain.
I have an Esp8266-01 with 1MB memory. I've flashed it with an official AT firmware V2.0.0 of espressif with the help of this tutorial-arduino as a usb/TTL-: "<a href="https://www.allaboutcircuits.com/projects/flashing-the-ESP-01-firmware-to-SDK-v2.0.0-is-easier-now/" rel="nofollow noreferrer">https://www.allaboutcircuits.com/projects/flashing-the-ESP-01-firmware-to-SDK-v2.0.0-is-easier-now/</a>", and it was a successful flash.
However, when trying to send AT commands in the serial monitor at different baud rates nothing happens.
I'll provide you with all the information down here:</p>

<ol>
<li>Schematic for both flash and normal mode:</li>
</ol>

<p><a href="https://i.stack.imgur.com/dvVfN.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dvVfN.jpg" alt="Schematic"></a></p>

<ol start="2">
<li><p>I used the official flasher tool from espressif</p></li>
<li><p>I used both Arduino IDE and Termite with no results</p></li>
<li>I've uploaded the blink sketch successfully into my module, but it never runs and blinks.</li>
<li>After lots of tries and resets I started to receive some information:
<a href="https://i.stack.imgur.com/HKDVV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HKDVV.png" alt="Reset info"></a></li>
</ol>

<p>But still no answers from this module!!!
Could you help me, please?</p>
 37622: <p>The tutorial is to flash SDK 2.0 AT firmware. The AT 2.0.0 firmware is build with RTOS SDK. The 2.0 AT firmware available on Espressif site was build with settings not compatible with esp-01. It is built for 2 MB flash and  communicates over pins 13 and 15.</p>

<p>The latest NonOS SDK AT firmware is 1.7.1 (SDK 3), but it requires 2 MB flash too. It is possible to flash it to 1 MB module with the 2MB-c1 parameter with esptool.py. (The OTA update command will not work.)</p>

<p>GitHub user loboris (Boris Lovosevic) builds customized versions of AT firmware with SDK 3 for all flash sizes. You can download the files from his <a href="https://github.com/loboris/ESP8266_AT_LoBo" rel="nofollow noreferrer">ESP8266_AT_LoBo GitHub repository</a>. If you can't run his flash.sh utility, then for 1 MB flash you can Flash Download Tool with bin/upgrade/esp8266_AT_1_2.bin file and the right addresses for 1 MB flash: boot_v1.7.bin on 0x0; esp8266_AT_1_2.bin on 0x01000; esp_init_data_default.bin on 0xfc000 and blank.bin on 0x7e000 and 0xfe000.</p>
