read default Parameters in Ardupilot Bootloader

I want to read the default Parameters file of Ardupilot in the Bootloader to calculate its checksum and compare it with the stored Checksum in AP_Bootloader.cpp. I understood that we need to use AP_param.cpp. However, I am unclear which function to be used to read the default parameter file from AP_Param.cpp

I am using to make the custom parameters default and update the apj file as per the below instruction provided by Ardupilot