Never unplug the Black Berry while the device is upgrading. If you do, there are ways to get it working again, but it’s troublesome.
Official OS from other Carriers and Leaked OS: Why is DM not detecting the update after installing on PC?
Maybe you did not get improved performance, but on the contrary.
I was confused because it differs from the article ever read.-I am not the expert on this, maybe I forgot to write one or two steps.-Do not ever interrupt the upgrade process because it can damage the hardware.
Damage can also occur due to unintentional, such as power failure, lost internet connection, and is not a must that you must install DM (desttop manager) if u have slow connection, download only blackberry usb drivers here and install
It would offer to do the OS installation process (first right image below).
Process will run automatically like on online update process.
This will allow you to get to the step in which you choose what apps and settings you want to install on your Black Berry.