Unreliable setup

[geo.espressif]

I'm using a USB - UART converter device, connected to a ESP8266 device with a jumper mounted for going into boot mode. This seems to be the setup of many others I've seen:

However, I'm finding the setup extremely unreliable, the COM port bounces in/out in windows, and I can rarely connect via terminal to pull logs. Flashing is slightly more reliable, but sometimes the tool will fail to establish a connection. When this happens I usually disconnect the device, check the pins and try again. Sometimes this works. I've tried different chips, different USB/UART converters and different ribbon cables. I've tested all connections with a multimeter.

I'm just wondering if there's something fundamentally wrong here, whether this is something others have seen, or whether there was a developer setup Espressif might recommend instead.

[Triacon]

The voltage regulator on your uart<->serial converter can't supply enough power for the peak usage of the Wifi module.
Attaching a large cap. to the 3.3v most likely won't be enough. So power the module from separate power supply with 3 - 3.3v output. Disconnect the power from the USB module and make sure to connect the grounds from your power supply with your USB ground. Make sure you don't use two different mains phases or anything else that might give you ground currents or it might damage your computer.

Kind regards
Jimmy

[geo.espressif]

Thanks Jimmy, really helpful. We're setting up something with an external power supply now.

James