I try to flash an ESP12E microcontroller through an FTDI serial converter. It seems like the UART connection is a bit unstable, because when I try to flash it via esptool it often throws "Timed out waiting for packet header" error. Also when I thy to get the flash_id the same error occures at around 50% of the time. The simplier commands like get_mac and chip_id are working well.

I'm using an ESP module with wires soldered to its pads. It is put into a breadboard and it's connected to a USB-UART converter via jumper wires.

What could be the problem?

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    I have several 4 x ESP07's, 2 x ESP12E's and 14 x ES12F's ... the 07's and 12F's never give me problems, however, the two 12E's are unstable as hell when using FTDI, even flashing OTA whilst powered by FTDI cable is a 50/50 proposition - ditch the 12E's get some 12F's is my advice Apr 23, 2017 at 23:26

1 Answer 1


Power supply...

I designed a pcb for the ESP module, it works like a charm since then. Used a TC1262 regulator, a 100n ceramic and a 1000u electrolyte capacitor (maybe 100u would have been enough) very close to the Vcc and GND pins.

Seems like the ESP is really sensitive to the power supply stability.

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