I've been experiencing this since I installed my CC, and thought that fw 30+ would resolve the bug but it is still showing up.
Occasionally when I power up my PS2 from standby it will show the Sony logo (with the sound, etc.), as if I had booted into recovery mode. If I reset the unit the CC logo comes up fine and everything works. This doesn't happen every time and after the reset it works fine. I've never tried to boot a disc when the Sony logo comes up but maybe next time I'll try and see if I can boot anything other than an original. I thought I'd report this as maybe it's related to the timing issues that were causing the black screen with the upgrades? Or could this be an install/bad wiring issue?