I solved it this way: used "idf.py menuconfig" to change partition table to csv. created "partitions.csv" with 256KB of spiffs as "/storage": nvs, data, nvs, 0x9000, 0x6000 phy_init, data, phy, 0xf000, 0x1000 factory, app, factory, 0x10000, 0x100000 storage, data, spiffs, 0x110000, 0x40000 python .....