yes you are right. I discussed this a few hours later on Gitter.
I will continue with spi_flash_read & co,
Already made some coding, and atm able to make dumps of flash into serial console.
This for example is part of your spiffstest.bin, you provided a few days ago.
Next I will try to write, and look how to erase first.
ESP8266 Arduino add-on
Arduino IDE 1.6.5