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?