Well, I can't explain otherwise why Punchout demands an update after installing cIOS (or Tetris Attack), even though it played fine just earlier... This has now happened on my bricked wii, my friend's wii, and my brother's. I figure, since I installed tetris attack with cIOS249, that might explain it. Or maybe cIOS is downgrading other IOSes when I install it? Then, installing a new IOS35 on top of a downgraded one kills the wii?
Or, if I install a new IOS35, while having channels on my system that were installed with a downgraded IOS35, would that explain the brick? Do these channels "still use" the IOS I installed them with, and freak out when it's not the downgraded one? I don't see how that could cause a full brick, though.
For what's it's worth, I took another look at the IOS35 from Punchout, and it's not a stub (1.6megs IRC), so the sabotage theory is probably out. My current theory is that installing cIOS does something to your other IOSes, OR Punchout is attempting to use/check IOS249 as an anti-piracy measure.
EDIT: The thing that gets my goat is that if Nintendo is trying to go after pirates, they got the wrong guy... I ALWAYS buy the discs for the ISOs I rip (for both Wii and PSP), and I prepaid for every chapter of FF4: After Years before downloading the leaked DLC. I probably buy more games now that I have hacked consoles, since they are more convenient to play (from hard drive / memory stick).