The VCP function is a little big buggy as it only seems to update RTS when the DTR is updated as well. So I had to make a small software tweak to delay the EN signal, in order to keep IO0 at a low state when EN rises to properly enter bootloader uart mode.
The factory-loaded firmware is working, I can send AT commands, connect to wifi-network etc. But it’s the loading of new firmware that isn’t working.
Please look at the included screenshot, and keep an eye on the red signal (EN)
First attempt: IO0 was not low and wrong boot mode was started, but ESP8266 is replying to sync command.
Second attempt: Also wrong boot mode, perhaps because bad timing of EN/DTR or the fact TXD was low. Don’t know.
Third attempt (and all following attempts): IO0 was low when EN raises and boot log responds with “ets Jan 8 2013,rst cause:1, boot mode:(1,6)”
But chip seems completely dead after sending it’s bootlog, no response to sync command from programmer, despite trying bitrates from 9600 to 115200
If anyone got any idea of what is going wrong or what I completely missed, please let me know before I'm going crazy