I'd say it's a loose wire, cause it worked fine and all of a sudden you only get to the PS2 browser. Another indication is that it can't load the upgrade CD, that should work always if the installation is ok.
But to do some troubleshooting you can try to boot the upgrade disc in recovery mode (power on, then 3x reset). And you could try to boot an original game with disabled chip (power on, then 6x reset).
If you really have a CC2.0 you can't use BM from MC, but only from the cflash. And BM is definitely needed for the CC2.0, without BM you'd only get a black screen and not the PS2 browser (another indication for a loose wire).
If you want to know what that "corrupted data" is, you'd have to use LaunchELF's filebrowser. The damn stupid $ony browser can only display gamesaves correctely, normal data files are always shown as "corrupted data", which doesn't mean that they are really corrupt.
best regards Jones23