Cold flash working without problem (from your output) and if you did not saw NOKIA logo after cold flash you have 1) bad/uncompatible USB cable/port/computer for normal flashing or 2) your n900 is broken in HW and cannot start NOLO.

Try another usb cable, usb port and computer. I have 1) problems with my usb some 2.0 and all 3.0 ports. Only one combo usb2.0/eSATA port working fine for flashing. But any other usb device which I have working fine with any my usb ports...