ESP8266 Community Forum

As I understand, ESP8266 does not have flash memory. The program is stored on the serial flash IC so flashing a new firmware does not involve ESP8266 at all. You just need to write firmware to a standard serial flash IC which is very easy. All you need is a FLASH programmer. Heck you can even cook up a flash programmer using your favorite micro controller. Let me know if I am missing something.

My rapsberry pi waits to dump the flash contents


the more challenging part will be to debug this thing! any hints on cheap debug hardware?
I'm thinking of using a stm32 discovery board as black magic probe...

Something like this should work for a JTAG.
https://www.olimex.com/Products/ARM/JTAG/ARM-USB-OCD-H/

That unit also contain a UART to USB converter and small power supply.

RC is a very old Xtensa product release. Latest is RF. The latest RF software can be used on these older cores. And in the latest software, all those _xtos_... functions are freely licensed, no need to rewrite.