Usually, when a comparatively major firmware update gets released, the first thing the homebrew community does is scrutinize the changelog. Not just the one officially posted but also the things that Sony doesn't mention. Then, it's usually decrypted pretty rapidly by one group or another. Finally, someone posts a YouTube video showing what is allegedly a working CFW version of the official update.
Things didn't go any different with OFW 6.00.
Custom Firmware Updates:
- Custom Firmware 5.50GEN-B2 released. Link
- No plans for custom firmware 6.00 M33. Link
- PSP firmware 6.00 decrypted. Link
- Fake or legit? PSP CFW 6.00 beta video. Link
- PSPCleaner v1.5. Link
- LightMP3 2.0.0 RC3. Link
- PSPConstructor, a PSP game maker. Link
- LuaPlayer Euphoria v6. Link
- AVEC GPS V4 (1.50 Kernel). Link
- Ebootr Beta homebrew replacement for PBP Unpacker. Link
- LuaPlayerHM source code released. Link
Quick note about that CFW 6.00 video up there. A lot of people are calling shenanigans on it. See, in 6.00, the Network Update icon has been renamed to System Update. As frequent commenter Om3ga Ars3nal pointed out, "the Person showcasing this "New Firmware" covers the word "NetworK" up with his thumb, but does not cover it all the way, leaving "ork" visible." Others have spotted it too.
So, fake? Real? Watch the video again and just decide for yourself.