edit: I'll gladly take a downvote for this, you're talking about screaming at customer support and IM getting downvoted. Constructive group we have here.
My device has been stuck in a perpetual (failing) update loop like many others. No patch was ever released. There's no known way without specialized hardware (PS3Key) or out-of-warranty RMA. I don't want to invest in either solution.
Through much trial and error, I found a way to make the update work every time. This may look stupid, but I swear it works:
1. Try the update. It fails.
2. Turn off the console.
3. Take the hard drive out.
4. Turn on the console. It will fail to boot and shutdown.
5. Put the hard drive back in.
6. Turn on the console. The update will start again and succeed.
I have no idea why this works, it makes no sense to me. But it's been working this way without fail for a few years.In my opinion, it's a poorly designed update mechanism that makes it prone to failure. There should be some redundancy built into the process so that the machine can always force itself back to a "known-good" state and at least access the recovery menu.