[Q] Tmo Samsung S4 (SGH-M919) with Google Play Edition, need help

(this belongs elsewhere but 10 posts...)

I have a rooted S4 and just installed Dandvh's Google Play Edition v.20150919 (http://forum.xda-developers.com/show....php?t=2539361) rom. I used TWRP to install, wiping everything but internal storage, then flashed the rom. Installed fine, no errors. Took the usual bit of extra time to boot the first time then up and running clean and stable. The issue is that the OTA Updater app doesn't work, severely limiting my ROM options. It didn't install as part of the rom install, though I'm not sure if it's normal to just get it off the play store. I get an error message about not being compatible with the ROM and can't access it (error message screen cap below). Just in case, I wiped the phone and flashed again just to be sure, same result. The OTA Updater is important as this is where you can change kernals, audioFX stuff, toggle advanced power menus, and quite a bit more. When I used this ROM during the first part of the year OTA Updater worked just fine but I switched off in July to try another ROM so maybe something with the ROM has changed? I tried searching for any comments in the thread to indicate either that something changed with OTA Updater or if anyone else had a similar problem, found nothing. Would appreciate if anyone might know why OTA Updater isn't working or how I might correct it. Thanks.


Edit: I haven't changed the model number to SGH-M919 (as seen in the screen cap) in build.prop yet as if I can't get this ROM to work right I'll need to flash something else.

Version and Build Screenshot
https://imgur.com/SQ6ie5i

Error message
https://imgur.com/TfWN7p2

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?