The core conflict regarding the downgrade from 13.02 to 9.00 lies in the reality of hardware security. Unlike early gaming consoles where software versions could be swapped with relative ease, the PS4 employs a sophisticated security architecture involving "fuses" on the motherboard. These are not physical glass fuses, but electronic "efuses" that are blown by the system software during the update process. When a PS4 updates its firmware, it burns specific fuses to prevent the system from ever booting an older version of the software. This creates a one-way street; once a console has passed a certain firmware threshold, the hardware itself recognizes the older software as unauthorized.
The console does not “remember” the old firmware; it only knows the minimum version allowed. Downgrading without replacing the Syscon or its flash/eFUSE region is impossible. ps4 downgrade 13.02 to 9.00