If you going to enter safe mode , just use the Internet option , then no usb isues at all :)
4.00 firmware is out tommrow anyway :) as indicated on psn blog :)
you might have to re int the Hdd , as the data on the hdd maybe corrupted due to the power isues you had. That's an option in safe mode .
i hope you backed up the game files and save game files :) as Sony do say to do :)