Thanks to PS3 developer cotojestwtf who has released a nice tool called Yet Another Bypass v1.0. This tool gives you the option of not needing to update to 4.00 OFW. There is a catch as it only works with 3.7X firmware.
Here are the instructions but remember 3.7X FW only.
"1. Start bat file YABStart
2. Set up on PS3/Proxy Settings IP: of your computer
3. Set up on PS3/Proxy Settings Port: 27 u can change them on config folder (port.txt)
4. Connect on PSN
Succesfully bypassed 4.00 on 3.72/3.73
NOTE:
-If you want turn off proxy, you must do it on your TASK MANAGER (CTRL + ALT + Delete). Search process PS3YAB.exe.
-No It no gain you PSN on CFW.
You can download all stuff from PSStore without error.
Enjoy."
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