Nokia N900 :: Power On And USB Charging Error?

I find that when the phone is on charge I can never power it on, it simply reboot repeatedly after the logo shows up, it is on V 10.2010.12-9.I also have problem with the USB charging, I can charge the phone with the PC via a standard USB cable, but the same cable doesn't not charge with external battery pack, and I got a special cable that charge both with PC and external battery pack, but it does not do data transfer, so I have to carry 2 cables and spare battery. I also find that, the phone is unable to charge a completely ran down battery, it must be charge on the dock, I think that's why the set comes with a dock charge, other non Nokia USB charging phone also comes with the dock charge (in my region), so I think this is a common problem of USB charging, and the reason may be the charging is s/w controlled, if the battery is dry the phone won't work so no