[psychotic]

this happened to me, I did a hard reset, it went back into serial mode, then I plugged in the usb and started the flash again. luckily it worked. I'm not sure if you've done this... you said you've tried to update it with the bootloader screen on, but you didn't mention a hard reset. The hard reset "refreshed" my bootloader screen and allowed the rom to load properly. good luck.