That's a known bug. Once X starts, the display should come back on. I'm not sure if your system needs to use the Radeon or Intel driver.
I'd prefer intel, because radeon can't work on Linux too. But if possible enable radeon too, that will be more advantageous for me than linux.
That's also why we want X to handle the automatic module loading; if the KMS modules get loaded too early (or when booting single-user) the console wouldn't be usable.
Yes, I already did that, and the system became unusable :P.