Dial *#0000# . You should see:
How to identify the correct file
For the classic Nokia 6300 (RM-217) , the most stable and feature-rich firmware version widely recognized as the "better" or latest update is nokia 6300 rm 217 flash file better
A flash file, also known as a firmware, is a type of software that is used to update the operating system of a mobile phone. In the case of the Nokia 6300, the RM 217 flash file is a specific version of firmware that is designed to improve the phone's performance, fix bugs, and add new features. Dial *#0000#
Perform a hard reset using *#7370# . If the phone reboots without error, your flash file is clean. also known as a firmware