Thought I would bring this to everyone’s attention as this hasn't been posted yet.
Credit goes to NextGenUpdate members D19RNY and ThereThatGuy
Bypass only currently works on 3.30 firmware, so I have no way of confirming whether this works as I am on 3.41!
Here is a SIMPLE guide on how to bypass the firmware. You must currently have firmware 3.30 to use this method. It is possible to do with lower firmware.. Also, we might be able to downgrade doing this, but I'm not risking corrupting my HDD.
PS3 Proxy Server
A PC and PS3 using Same Router
Create a new .txt. document named "ps3-updatelist.txt" Put this in it
1. Set up the PS3 proxy server. Put your IP in the box, also make sure to check the PS3 box and hit start.
2. Go to the Replace files Tab and in the left box put
3. In the right box browse to your ps3-updatelist.txt and click it.
4. Sign In, it should not ask you to update firmware. Congratulations, you are playing online with your PS3 on firmware 3.30!
This is possible without the proxy server! If you have a parental control router, redirect the updatelist URL to the URL of an older updatelist! They are uploaded all over, so they are easy to find.
Original source: How To Bypass 3.55! - NextGenUpdate