It should give the G1 slash when attepting to enter recovery mode.
Hold Home > Press and relase Power > wait for vibrate > release home > wait for recovery screen.
That is the proper method. If ti doesnt work, most likely bricked.
this just happened to me while trying t o partition my sdcard.. right now im lading the cianogen rom again to see if it fixes it... i dont know what does the sdcard has to do with phone mem.