Use the Raspberry Pi to write the patched dump back to the NOR chip.
They are almost always fake or scams asking for:
Downgrading a PlayStation 4 Go to product viewer dialog for this item. from firmware
So, what happens if your PS4 accidentally updated to 10.50, or you bought a used console with 10.50 pre-installed? You want to go back. But can you?
Downgrading a Go to product viewer dialog for this item. from firmware 10.50 to 9.00 is not possible through simple software settings or USB updates. Sony prevents downgrades to block security exploits found in older versions like 9.00.