DO NOT COLDFLASH when your device does not need it!
Coldflashing is solely to restore a broken bootloader, and obviously your bootloader isn't broken since it boot up to display stuff on screen and even starts flashing procedure. If it was broken then your device would act _really_ bricked and not show any sign of life (except BOOTROM "hello" via USB, that gets detected by flasher). ONLY THEN you should consider coldflashing - after you made sure it's not your battery that's defect.

It's not like coldflashing could do massive harm to your device since you can repeat it under nearly all circumstances (unlike flashing BIOS of your PC, which might render your motherboard bricked when you abort it), but definitely it won't usually fix anything for you, and just may introduce another level of failure cause that complicates things even further.

on the errors you encounter: try a better USB cable and a different port on your PC, those errors *might* be simple data corruption on USB protocol.

/j