ESP8266 Community Forum

Hello,

I have purchased a bunch of ESP8266-01, which are preloaded with the AT command firmware. After reset it sends 'Ai-Thinker ... ready' and accepts AT commands properly. Unfortunately I cannot flash successfully my own firmware into these modules. After flash it sends permanently scrambled characters.
Is for these modules a specific flash method necessary or did I purchase trash?

Many thanks for any hint.
Walter

Programming the ESP-01 is actually not that difficult, once you've got the hang of it.
Since the ESP-01 isn't very n00b-friendly, it's always advised to start with a development board first and when you're comfortable with the ESP8266, you can wander along discovering individual ESP modules.

The ESP8266 is pretty strict when it comes to programming (and at some point using) it: the power supply must be able to deliver a solid current of at least 500mA at a stable 3.3V.
Using shortcuts (like taking the power provided by an FTDI and such) just doesn't do it (reliably).

There are some walk throughs for the ESP-01 though, like this one on AllAboutCircuits.com.

That should get you going, but if you have any question, please don't hessitate to ask them here.

walt22 wrote:After flash it sends permanently scrambled characters.

Those "Scrambled" characters are (most likely) characters sent at a different baud rate than you've selected in you terminal program.
Remember that the ESP boots up at 74880 Baud and switches over to whatever rate is selected in the flashed program (most of the time it's at 115200 Baud, sometimes 9600 Baud)

Hello,

Many thanks for your quick and useful answer. But I have already flashed more than a dozen ESPs of different flavor, ESP-01, ESP-201, NodeMCU, all successfully. I tried to flash these 'bad' ESPs with esptool.py, esptool-ck and even with ESPFlasher with different parameters - no success.
I will double the charging capacitor and give them a last chance before they go to trash.

Best regards
Walter

sometimes I have the same problem. I flash them either with the NodeMcu flasher or with the espressiv tool and the "blank.bin" file for all relevant addresses. This (snake oil?) usually gets them going again ...
The "blank" option of the esp-tool should do the same but seems to be broken...