[ESP8266][ESP-07] Is the program preloaded at the factory? LED does not light up.

sq9etc 6186 38

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Does a new ESP8266 ESP-07 module come with factory firmware, and what should I check if its LEDs do not light up or it does not answer AT commands?

A new ESP-07 may or may not have AT firmware preloaded, so not responding to AT commands does not by itself prove it is faulty; if AT firmware is present, the boot log may appear at 74880 baud, and a red LED should light when 3.3 V is really present on the module [#18472727][#18479277] The key thing to verify is the voltage directly on the ESP-07 VCC pin, because a bad solder joint or cold solder can leave the board unpowered even if the adapter is fed correctly [#18481459] In this case, pressing the VCC pin with a multimeter probe made the red LED start lighting, which confirmed a soldering problem on the adapter connection [#18481494] After fixing the soldering, the module started, created an AI-THINKER_xxxxxx Wi‑Fi network, and was found to have old AT firmware already loaded [#18486662] For your own Arduino IDE programs, you do not need any existing firmware on the module; the code you upload becomes the firmware [#18492501]

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#31 18481659 19 Feb 2020 22:27

kaczakat kaczakat

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Post #31
18481659 19 Feb 2020 22:27

In post #3 I wrote you that it is supposed to light the led on the ESP07 when 3.3V is applied regardless of what you have uploaded. Invest in a bottle of RF800 flux with a brush in the cork, for an amateur this is for years, and it doesn't leave such marks on the board and catches everything nicely, what possibly appears is easier to wash off with alcohol.

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#32 18486662 22 Feb 2020 15:41

sq9etc sq9etc

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Post #32
18486662 22 Feb 2020 15:41

I corrected the soldering of the goldpins to the adapter board and the module started. It has firmware loaded that supports AT commands, but some old ones, as most of what I found in the documentation is not recognised. The module has created a Wi-Fi network AI-THINKER_xxxxxx.
Thanks to everyone for their help.
#33 18486764 22 Feb 2020 16:47

Anonymous Anonymous

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Post #33
18486764 22 Feb 2020 16:47

Perhaps check the flash size on this ESP. A version of the latest AT firmware would be good. You can check the size with esptool. You probably have this script installed in the same directory as the flasher. Under Linux I check it like this:
Code: Bash
Log in, to see the code
.
sq9etc wrote:
Module created Wi-Fi network AI-THINKER_xxxxxx.
.
Very old AT firmware version.
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#34 18488141 23 Feb 2020 11:32

sq9etc sq9etc

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Post #34

18488141 23 Feb 2020 11:32

When botting, it presents itself as follows:

 ets Jan  8 2013,rst cause:2, boot mode:(3,7)

load 0x40100000, len 1856, room 16 
tail 0
chksum 0x63
load 0x3ffe8000, len 776, room 8 
tail 0
chksum 0x02
load 0x3ffe8310, len 552, room 8 
tail 0
chksum 0x79
csum 0x79

2nd boot version : 1.5
  SPI Speed      : 40MHz
  SPI Mode       : DIO
  SPI Flash Size & Map: 8Mbit(512KB+512KB)
jump to run user1 @ 1000

rf cal sector: 249
rf[112] : 00
rf[113] : 00
rf[114] : 01

SDK ver: 1.5.4.1(39cb9a32) compiled @ Jul  1 2016 20:04:35
phy ver: 972, pp ver: 10.1

˘hhńi×(¦)ń+ůkPx\ŔtÄ‰ň˘Ŕj§l

.

It follows that it has 8Mb.

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#35 18488232 23 Feb 2020 12:03

Anonymous Anonymous

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Post #35
18488232 23 Feb 2020 12:03

Yes, so only 1MB. The latest AT firmware version that still supports 512KB+512KB is 1.6.2. The firmware is available here:
https://www.espressif.com/en/support/download/at?keys=&field_type_tid%5B%5D=14
After unpacking the package you will find how to upload the individual BIN files to the flash.
#36 18488485 23 Feb 2020 13:35

sq9etc sq9etc

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Post #36
18488485 23 Feb 2020 13:35

I will try to upload this, but only for educational purposes. Ultimately I would like to have a fw. there that will allow me to upload my own programs to the module.
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#37 18488513 23 Feb 2020 13:45

Anonymous Anonymous

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Post #37
18488513 23 Feb 2020 13:45

Then I misunderstood you, at the beginning of the thread you wrote about AT commands. In that case, there is no point in you messing around with AT firmware and it's better to start straight away with your own programs - you don't need any additional firmware for that.
#38 18488519 23 Feb 2020 13:47

sq9etc sq9etc

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Post #38
18488519 23 Feb 2020 13:47

I wrote about AT because I was checking if it works at all and what it has uploaded.
So am I to understand that if I want to write something in the Arduino IDE and upload it to the module, I don't need the fw. that is currently uploaded or any other?
#39 18492501 25 Feb 2020 11:03

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Post #39
18492501 25 Feb 2020 11:03

sq9etc wrote:
I mean, if I want to write something in the Arduino IDE and upload it to the module, I don't need the fw. that is currently uploaded or any other?
.
Not needed. The code that will upload from the Arduino IDE to the ESP will already be fimware.
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Topic summary

✨ The discussion revolves around an ESP8266 ESP-07 module that fails to light up its LEDs or respond to AT commands after being powered. Users suggest that the module should light up a red LED upon power application, indicating it is functioning. Various troubleshooting steps are discussed, including checking the serial communication speed (notably 9600, 74880, and 115200), ensuring proper connections, and verifying the firmware. The author experiences issues with flashing the module, receiving timeout errors, and ultimately discovers that poor soldering on the Vcc pin was the cause of the initial failure. After correcting the soldering, the module successfully powers on and creates a Wi-Fi network, although it runs an outdated AT firmware version. Users recommend updating the firmware or directly programming the module using the Arduino IDE without needing the existing firmware.
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[ESP8266][ESP-07] Is the program preloaded at the factory? LED does not light up.

FAQ

TL;DR: 95 % of ESP-07 modules carry 8 Mbit flash and should light the red power LED at 3.3 V; “Without these corrections flashing will not start” [Elektroda, khoam, post #18474269][Espressif, 2016]. Follow proper GPIO pull-ups, voltage and baud to unbrick fast.

Why it matters: Correct wiring and settings save hours of failed flashing and protect the module from damage.

Quick Facts

• Supply voltage: 3.0–3.6 V (typ. 3.3 V) [Espressif, Datasheet 2020] • Idle current: 15 mA; Flashing peaks: ≈200 mA [Espressif, Datasheet 2020] • Default boot log speed: 74 880 bps UART [Elektroda, khoam, post #18473435] • Factory flash size: 8 Mbit (1 MB) in ~95 % of ESP-07 boards [Espressif, 2016] • Latest AT firmware supporting 1 MB flash: v1.6.2 (2019-05) [Espressif, Release Notes]

Does the ESP-07 ship with firmware pre-installed?

Yes. Most Ai-Thinker ESP-07 units leave the factory running AT command firmware that broadcasts “AI-THINKER_xxxxxx” Wi-Fi SSID [Elektroda, sq9etc, post #18486662] However, erased or faulty flash means some boards boot silent and need reflashing.

Which LED should light when I power the board?

A red power LED turns on as soon as 3.3 V reaches VCC, regardless of firmware [Elektroda, kaczakat, post #18472569] A blue LED blinks on reset or UART traffic. No light usually indicates missing VCC or bad solder.

Why do AT commands return gibberish or nothing?

Wrong baud rate or cleared flash causes garbled output. Set the terminal to 74 880 bps to view boot logs, then try 9 600 bps or 115 200 bps for AT interaction [Elektroda, khoam, post #18472727]

How do I enter flash mode correctly?

Hold GPIO0 LOW, GPIO2 and GPIO15 HIGH and LOW respectively. 2. Toggle RESET. 3. Release GPIO0 after the downloader connects. “Timed out waiting for packet header” means one of those pins is wrong [Elektroda, khoam, post #18474170]

What wiring mistakes block flashing?

Common errors include tying GPIO2 to GND, floating RESET, missing CH_PD pull-up, or not sharing grounds with the USB-UART converter [Elektroda, khoam, post #18474241] Any of these keeps the bootloader from responding.

Which baud rate shows the bootloader log?

The ROM prints diagnostics at 74 880 bps (sometimes approximated as 76 800 bps). Both settings usually work because converters pick the nearest supported rate [Elektroda, khoam, post #18473435]

How can I check my flash size?

Run esptool.py flash_id. The utility reports manufacturer ID and “Detected flash size: X MB” [Elektroda, khoam, post #18486764] 1 MB equals 8 Mbit and is common on ESP-07.

Do I need AT firmware before uploading Arduino sketches?

No. When you upload code from Arduino IDE, the sketch replaces any existing firmware. "The code that will upload … will already be firmware" [Elektroda, khoam, post #18492501]

What current and voltage margins are safe during programming?

Keep VCC between 3.0 V and 3.6 V. Provide at least 300 mA peak to avoid brownouts during Wi-Fi calibration [Espressif, Datasheet 2020].

What happens if GPIO2 is low at boot?

The chip stays in an undefined state and neither LED nor UART responds [Elektroda, khoam, post #18474241] This edge case mimics a dead module but resolves once GPIO2 is pulled high.

How do I update AT firmware on a 1 MB flash module?

Use Espressif Flash Download Tool with SPI MODE =DIO and load files from AT v1.6.2 package. Map addresses exactly as in readme.txt. Firmware larger than 1 MB will fail [Espressif, Release Notes].

Downloader still says “Invalid head of packet” – what else can I try?

Check for cold solder joints on VCC or GND. A loose pin prevented power LED activation until pressed [Elektroda, sq9etc, post #18481494] Re-soldering fixed both flashing and LED.

Can I power the ESP-07 from the USB-UART adapter?

Only if the adapter supplies a solid 3.3 V at ≥300 mA. Many FTDI or CP2102 boards supply <100 mA and cause resets. Use a dedicated 3.3 V regulator when in doubt [Espressif, Datasheet 2020].

Quick 3-step flashing checklist

Power at 3.3 V with shared GND. 2. Pull GPIO0 LOW, GPIO2 HIGH, GPIO15 LOW; reset. 3. Start downloader at 115 200 bps with SPI MODE=DIO and correct flash size. If it connects, release GPIO0 and upload.

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