Many people got the '8002F325' error on Rebug and other Custom firmware.
If you tried to install a newer CFW, or your PS3 data is corrupted from other reason (failed to restore ps3 system, HDD failure, power failure etc), you will get this error and you can't install or update the CFW.
Here is a simple solution. I've tried every Rebug CFW but I couldn't pass the error screen.
To fix this error, just download the 4.81 STARBUCKS COBRA v7.40 CFW from here. Unzip it, rename the file as 'PS3UPDAT.PUP' and place it into your USB flash drive (in the 'PS3/UPDATE) folder.
Now try to update the system again. Press Start and Select at the same time and wait. Your PS3 will install the CFW without any errors.
Now you can install the latest Rebug CFW if you want.