ESP8266 using different flash sizes – FOTA and Download tool
Which goes where – when using a bootloader for FOTA.
The files:
- master_device_key.bin – Obtained from Espressif Cloud
 - esp_init_data_default.bin – Stores default RF parameter values
 - boot.bin – bootloader
 - user1.bin and user2.bin – user firmware
 - blank.bin – blank settings , flash to get default parameters
 
- 512KB
 
- master_device_key.bin 0x3E000
 - esp_init_data_default.bin 0x7C000
 - blank.bin 0x7E000
 - boot.bin 0x00000
 - user1.bin 0x01000
 - user2.bin 0x41000
 
- 1024KB Flash
 
- master_device_key.bin 0x3E000
 - esp_init_data_default.bin 0xFC000
 - blank.bin 0xFE000
 - boot.bin 0x00000
 - user1.bin 0x01000
 - user2.bin 0x81000
 
- 2048KB Flash
 
- master_device_key.bin 0x3E000
 - esp_init_data_default.bin 0x1FC000
 - blank.bin 0x1FE000
 - boot.bin 0x00000
 - user1.bin 0x01000
 - user2.bin 0x81000
 
- 4096KB Flash
 
- master_device_key.bin 0x3E000
 - esp_init_data_default.bin 0x3FC000
 - blank.bin 0x3FE000
 - boot.bin 0x00000
 - user1.bin 0x01000
 - user2.bin 0x81000