SGH-M919 Firmware Questions

I am rather new to ARM platform devices and Linux. I have recently received a used Samsung Galaxy S4 SGH-M919 device.

I have been doing some research on these forums as well as genera searches on Google, but still have questions or issues in need of clarification.

Please correct me if any information here is inaccurate.

From what it seems the SGH-M919 and many other Samsung ARM devices utilizing the Android platform, have firmware given in three main parts:
PDA- Operating systems and settings
Phone- Cellular Modem firmware
CSC- Custom configuration for operator or sets of operators

Can the main firmware be entirely erased? If so, can the entirety of the main firmware be afterwards rewritten?

For other components included in the ARM device, such as the camera, Wi-Fi radio, Bluetooth radio, and others that may have flashable firmware, such as the SGH-M919, is, if it exists at all, the camera firmware stored as part of the main three firmware? If the other component firmware is typically not updated in the main three firmware, how can the firmware be applied? Should there be any compatibility problems (defect not withstanding), with the main firmware using different firmware versions of the other components?


Are there any ROM data or PROM, or otherwise flash that, once written, cannot be rewritten?

Where (or as part of what firmware) are the phone model number, IMEI Number, device serial number, and network component MAC addresses stored?

Is the recovery or custom recovery a separate firmware? If not, where is it stored?

How many writes are the flash chips inside the Samsung Galaxy S4 family typically good for?