ESP8266 Flash - Maximize SPIFFS size the board i use has 1MB Flash Size. My program however downloads 512K+ of data for processing.

Arduino Options i see are:



Ideally i would like to use 1MB of SPIFFS, is this even possible?

I don't use OTA, and compile with:



To minimise the footprint of the main sketch.

Thanks in advance.
No.

Even if you don't use OTA, your program is stored in flash. If you have 1MB of flash, there's no way you can use all 1MB for SPIFFS; that would leave no space for your program.

Here's a page showing how flash is divided up in an Arduino environment.

Even if you eliminate space for OTA images and the EEPROM, the Arduino environment will still reserve space for the sketch itself and for its wifi config and possibly a little more data.

You can never use 100% of the flash storage for SPIFFS.