the hard drive not working from cold boot could be from lack of power on startup, a few days ago me and a buddy spent some time trying to get USB hard drives working on other brand named car stereos, most stereos dont seem to supply enough power through USB since 2.5" hard drives are self-powered, the solution
1) get a 12v to 5v USB adapter from ebay, the kind made for recharging your USB device such as a GPS.
2) get a USB Y-cable that usually come with 2.5" hard drives or cd/dvd-roms
Its just suggestions, might help with the HDD not working off a cold boot issue, both items can be