Hello Ajmal
The issue with the config register is that it can be various values, and still function correctly. This document describes in detail all of the possible values for the config register. Even though it says “routers” it is the same for switches as well:
Now the 0x2102 is default for routers, but other devices like switches may have other values. Specifically, the 0xF is a normal config value for switches like the 2960 and the 4500 series for example. According to the documentation above, any value between 0x0002 and 0x000F does the following:
Specifies a default netboot filename. Enables boot system commands that override the default netboot filename.
In other words, it will boot up using the default filename of the IOS bin file, but allows you to interrupt this process to override it if you choose to. This is normal behaviour.
I hope this has been helpful!
Laz