Usage of system_uart_swap and flash programming

[nickagian]

I have this question regarding the usage of the system_uart_swap() function.

I will use it so that ROM logs during boot will not output on the UART connection between the ESP and the external module.

1) The thing is, I don't understand how this will work. Is it a setting that will be stored in the flash and will be applied from the next boot after running the code for the first time?

2) Also, after issuing this command, which pins should I use to serially load the flash? The normal TxD/RxD pins or the ones connected to the module?

[pratik]

The basic boot log will be displayed via UART0 anyway.
But the remaining log output will be shown from the alternative debug port. You can therefore use UART0 to print out only your own data. Debug messages will not interfere anymore.
During ESP8266 boot, just ignore the messages for half a second or so.

For flash programming, the pins will remain the same. This API is only used for printing log from other pins during user application execution. Nothing is permanently affected!