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 ...