: 9.00 must have been the last firmware version installed before you updated to 9.60. If you updated from 9.00 to 9.03, and then to 9.60, you can only revert to 9.03.
Safe Mode will refuse to install a lower firmware. The console will say, "The update file cannot be used (CE-34788-0)." This is a hard block. how to downgrade ps4 9.60 to 9.00
The only reason downgrading exists on older consoles (FW 5.05 or below) is because hackers found a way to gain full control at the hardware level before the fuse check happens. For 9.60, no such public exploit exists. and then to 9.60