> Apparently the USB chip has its own EEPROM? It is very common for a controller chip (USB, ethernet, bluetooth, wifi, SATA, etc) to contain a firmware EEPROM.

> Apparently the USB chip has its own EEPROM? It is very common for a controller chip (USB, ethernet, bluetooth, wifi, SATA, etc) to contain a firmware EEPROM. Whether you can flash this firmware without an hardware programmer depends on the implementation. For embedded systems like the rPi, it is common for the engineers to implement peripheral programming capabilities from the main processor. Most laptops have that capability too, on both my Apple and Lenovo laptops i've seen firmware updates happening. On generic PC motherboards, this is less common. It comes down to the board designer connecting the programming pins of the peripheral device to the main CPU I/O.