The ESP8266 -- SPI Flash

On all of my devices so far, when I probe for the type of flash, I get:
esptool -p /dev/ttyUSB0 flash_id
Manufacturer: e0
Device: 4016
This (sort of) indicates a Winbond W25Q32 flash chip (32 Mbit, 4 Mbyte). The "sort of" is because an actual Winbond device would have a manufacturer ID of 0xef not 0xe0. My guess is that this is a Chinese clone of a Winbond device, especially given the price point that ESP8266 modules sell for. Winbond is in Taiwan by the way.

When I first started with the ESP8266, I was ignorant and expected flash to be interfaces like a RAM memory chip, i.e. just mapped into the address space somewhere. This is most definitely not the case. An SPI interfaced flash chip is more like a disk drive. It has sectors and these sectors can be read and written. In fact a typical SPI device supports the following 15 commands:

I count 27 commands, so who knows why the data sheet claims 15.