Cheers. I bought the PS4 off eBay and it only arrived today. Was already on 5.50. Have turned off automatic upgrades so that I stay on 5.50. Do I need to delete the 5.55 update it has downloaded but not installed yet?If it had downloaded but not installed, you could have used the exploit to run FTP and then delete the downloaded 5.50. But unfortunately once upgraded, it cannot be downgraded. I believe they are working on the 5.50 exploit.
In the meantime, you can turn off the automatic updates and then remain on 5.50.