Espcomm_sync failed / PIO on Atom/Linux

After finally getting the /dev/ttyUSB0 on a U/Mint working with help of [1] (rebooting as mrred128 said) the next is:

Use manually specified: /dev/ttyUSB0
Uploading .pioenvs/sonoff-DE/firmware.bin
warning: espcomm_sync failed
error: espcomm_open failed
error: espcomm_upload_mem failed
*** [upload] Error 255

During ‘update’ the LEDs on FTDI are blinking. No LED(s) on the Sonoff Basic device show any activity … should it?

Any help for that?

[1] No access to USB-Port while using PlatformIO with Atom on Linux

Do you put the ESP8266 in bootloader mode before flashing? (pushing reset while holding down the FLASH button)

@maxgerhardt Thanks for taking care.
I think I’m doing it right: Pressing the Reset before connecting the usb cable. Then release the button and start the ‘upload’ of PIO.

Maybe I have killed the device because I wrongly connected TX and RX. Have to check with another device.

Same situation with the other device (ITEAD Sonoff Basic)

Going back to use the original SW/mode with eWeLink it shows the device is working well.
The FW was 1.6.0 and is now updated to 2.6.0 … maybe the old FW was not ‘able’ for an PIO upload? Will recheck …

Pressing reset before the USB cable (and thus power?) is connected shouldn’t have any effect?

They are two separate buttons. GPIO0 is labeld “FLASH” on NodeMCU boards and CH_EN (Chip Enable / reset) is the “RESET” button. At the moment power is applied (or the reboot button is pressed), GPIO0 must be low so that the ESP8266 will enter bootloader mode.

See Home · espressif/esptool Wiki · GitHub

Also maybe check at what baud you are operating? Decrease to a safe 115200 baud for example.

Used this GitHub - arendst/Tasmota: Alternative firmware for ESP8266 with easy configuration using webUI, OTA updates, automation using timers or rules, expandability and entirely local control over MQTT, HTTP, Serial or KNX. Full documentation at to understand what’s necessary. From that I understand the only one button on the device is connected to GPIO0, so pressing the button before connecting USB (powering up) should take it to bootloader mode.
Can you confirm that … or what has to be done with that device.

Ad the baud rate, it’s set to 115200.

Maybe it could help to have a look at the update log, see here:
On platformio.ini only env_default = sonoff-DE is enabled.
Is the size of the file ok?
-rw-rw-r-- 1 guenter guenter 1668688 Nov 2 13:03

Upps, seems the only problem was the TX/RX connection. Now all works, the device has Sonoff-Tasmota 6.3.0 von Theo Arends

Thanks! Hope to get the stuff working now :sweat_smile: