: If you want to exploit your PS4 in the future, do not install any further system updates.
If you are simply trying to reinstall your current firmware to fix corruption (and you mis-typed "downgrade"), here is the correct method: ps4 tool downgrade v1 00 install
If you encounter a website or video promising a "v1.00 Downgrade Tool," be aware of these significant risks: : If you want to exploit your PS4