オリジナル投稿者： Bobbieee ,
This is a problem with ALL Lithium ion batteries... if they have sat on the shelf too long and become completely discharged, it will be very difficult to put a charge on it. Lithium ion batteries should not be completely discharged. I have the same problem now with my iphone 4s - replaced the battery and apple logo is flashing. Tried to restore the iphone but I get an error 21 in iTunes. The problem is during restart of the phone during the restore process - because the battery is completely discharged, the phone shuts off momentarily instead of restarting. That is why itunes fails on the restore process. Don't fall for the $9 iphone battery trick - the old saying "you get what you pay for"...