These are almost always scams or malware. The PS4's security system is specifically designed to prevent this.
Use community tools to modify the dump to trick the console into booting the inactive slot. Write/Flash: Flash the patched data back to the NOR chip. Reassemble & Test. Safer Alternatives to Downgrading
For the average user: The risk of a permanent brick is over 50% for a first-timer. You are better off selling your 1302-error console for parts and buying a used PS4 on 9.00. ps4 downgrade 1302 to 900
The console's operating system and core boot files are split across the main hard drive and a localized serial flash memory chip.
If the patch worked, the console will no longer throw error 1302 because it is now looking for BD handshake version 9.00, and your drive is either compatible or bypassed. The firmware will install, and you will see a successful boot. These are almost always scams or malware
Currently, the PS4 scene operates on a specific exploit kernel. For a long time, firmware was the gold standard. Later, exploits were released for 6.72 , 7.55 , and finally 9.00 .
If you were meticulous enough to take a complete hardware dump of your console's Syscon and NOR flash memory back when it was natively running firmware 9.00, you are in luck. Write/Flash: Flash the patched data back to the NOR chip
If your goal is to play older versions of specific games (rather than the system firmware), you can use tools like RewindPS4 on GitHub . This proxy tool allows you to: Intercept download requests from your console.