I'm having the same exact problem! 99% done everytime and then it gives me 8002F994. I've tried USB, wireless, and wired. Same error everytime! I've reset the system, and am about to try reformatting, but wanted to read what the forum says first.
There's no way that a PS3 that works fine in every other way can just be broken (especially when others are having the same exact 99% problem!). This is a problem on Sony's end! I refuse to, once again, cough up $150 to send it back. My history with PS3 is that it goes out at about 1 month after warranty everytime. But in this instance, I think it's the patch that's the problem!
I received a message from Sony regarding my problem...
We apologize for any inconvenience you are having updating your PlayStation(R)3 computer entertainment system.
There are some troubleshooting steps we can advise that may be able to help you resolve this issue. Please refer to the following links for steps on how to resolve this issue:
Article Title: Troubleshooting the system software update
Article Link: http://playstation.custhelp.com/app/answers/detail/a_id/309
* Safe Mode option 3 or 5 (Warning, option 5 will erase all content on your PS3™ system.):
Article Title: Safe Mode
Article Link: http://playstation.custhelp.com/app/answers/detail/a_id/1488
In the given case that you need to use option 5 in Safe Mode, we suggest that you back up your any data that you wish to save using and external hard disk drive, or a USB Flash Drive. The links below will assist you with the procedures.
Article Title: Saving videos
Article Link: http://playstation.custhelp.com/app/answers/detail/a_id/1492
Article Title: Using the Backup Utility
Article Link: http://playstation.custhelp.com/app/answers/detail/a_id/798
Article Title: Copying games
Article Link: http://playstation.custhelp.com/app/answers/detail/a_id/799
If these steps are unable to help, your system may need to come in for service. You may submit your own Exchange Order using our Self Service Exchange for quick and easy processing on the Internet. Please note this is only available for United States residents. Other restrictions may apply. Please visit our Online Service Request page for more information.
I tried everything, including the nuclear option (reformat). Nothing has helped. Same error every time. So, according to the message, I would need to send it in. This unit was a refurbished replacement I got back from Sony last summer (not the one I sent in, for a BluRay laser failure). That service was JUST out of warranty (of course). This is turning into the biggest money pit imaginable! I am holding out hope (Ha!) that Sony will make this right.