I can't grab the firmware either. I just tried and figured since I missed the initial DL period I would be okay. No dice, stuck at 4%. I'm sure it has something to do with Akamai servers or whatever Sony's using to distribute these files. It happens with Podcasts occasionally, the file propagates across the system and some of the servers only get a partial DL, so when you go to grab it you only get a partial. When you reboot or whatever you just happen to get a server that has the whole file, so you're okay. But it's a crapshoot, rebooting is no guarantee.
I'm pulling the file down on my PC now, I got the link from the terrible forums on the Playstation site. The first time I tried it on the PC I only got 10.1 MB, which is probably what the PS3 is getting when it craps out.
This is the second time I've had this problem, BTW. There was a firmware release two or three back that I had the exact same problem on, but this one certainly seems more widespread.
Opinion: There's no excuse for this problem STILL existing over a day after the FW was released. Whoever's in charge of SCEA's online stuff needs their ass kicked. Where the hell are my downloadable PS1 games, BTW? Japan has shit-loads of great ones and we get a trickle of crap. Sony can't afford to suck so badly in any area considering the shape they are in. This is not a biased opinion, it's the fucking truth.