In response to the downgrade tool, Sony released a series of firmware updates (e.g., 4.10, 4.20) that patched the vulnerability exploited by the tool. These updates effectively rendered the downgrade tool obsolete.
Downgrading is not universal. It generally requires that the console has previously been on a lower firmware or that unique console keys (from a NOR dump) are used. ps4 downgrade tool
This isn't a true version downgrade, but if your system is crashing, you can use the official PlayStation Reinstallation file via a USB drive in Safe Mode to clean the OS. Common Tools & Methods In response to the downgrade tool, Sony released