I've seen, quite often actually, a circuit that will have an eeprom or flash chip soldered next to the application chip. Take a look at the ESP8266, it has some kind of programmable memory that sets up the SoC.
My question is how was that eeprom/flash chip programmed if there aren't any programming ports on the application board? Is there like some pogo-pin programmer used during assembly or a socket that they drop each and every one in before soldering? Those options seem incredibly time consuming.
Best Answer
I can't speak for the ESP8266, but in most cases, the blank chips are sent to a programming house that has equipment to mass-program them, either in a row of sockets or, in the case of large production runs, with an automated system that automatically runs each chip through the programmer.
In many cases, the board assembly house contracts with the programming house to provide the programmed chips.