I got this in the mean time. Pulled 5.1 and then pulled g22cfbf30c3 form github. Ended up with idf.py version: ESP-IDF v5.2-dev-1912-g22cfbf30c3 , which successfully built factory_demo project for the box. Thanks

Where can I download binary file: ESP-BOX-3_Demo_V1.2.4 - a original firmware for the box 3 (I think 1.2.4 is the last version, but I might be wrong)?
Is this the same as esp-box/examples/factory_demo ? If it is, which ESP-IDF version I should use? I was trying with several, but I was not able to ...