galaxy3 update that keeps updating for 3 days plus!
It is unlikely that your phone is useless. From the symptoms you state, it sounds like you have done one or more of the following,


Rooted your phone
Unlocked the bootloader
Installed a custom recovery
Installed a custom ROM


If even any one of these is true, the OTA update will fail and redownload itself because it thinks it was a bad package download.