I am pretty certain there are some bugs in the update program that is included in the PUP. It's a pretty nasty and apparently elusive bug that Sony cannot seem to find and fix (or can't fix). If you look at the Sony forums, the bug has been around for a while, but it got worse when 3.0 came out, because they went and touched that code for the new SLIM hardware. That code has to figure out what hardware it's running on, and load the correct firmware into the correct flash. So, every time you do an update, you have a small chance, but significant impact, of mucking up your PS3 because that program does the wrong thing.
And I believe Sony would want to fix the problem, if they could find it, because it's causing the same problem on brand new SLIM units (under warranty, and thus fixed on Sony's dime). I believe the problem is more widespread than Sony would like you to believe because they started offering refurbished SLIM's as a replacement option. That likely means they are running out of older refurb PS3 units very quickly, and one day, may not even be able to offer anything but a refurb slim unit. They don't owe you an older model (your warranty expired, Sony is doing you a "favor" by offering a replacement at a reduced cost).
What is worth noting for those conspiracy theory types... you only get a 90 day warranty on a refurb. So, if the update process causes the problem, then simply don't publish updates within roughly 90 days of each other. Wait for the warranty to expire first! Sony's got the EULA to protect them (firmware updates are at your own risk according to Sony).
And so... I am still on 2.76 - no working bypass to get to the PSN Store to buy DLC, no online gaming, no new Sony Pictures BR movies, and no PS3 games since 3.01 came out... just me and my partially functional PS3.