[Sprint Samsung Galaxy Note5] nofitbox:
Adding captures

Thank you for your great work and for have all well explained

Detail 1:

Previous week I had tested all said in that post of the link you put above but there is a problem with that possible solution and is that once you take the update to OI6 or use the OI6 TAR, YOU CAN NOT GO BACK TO OGD, and OGD is the first firmware available for this model (N920P). So after the (OI6) Stock ROM you can't downgrade to the original OGD. I tried to downgrade and Odin always gave an error and no possibility to flash the OGD stock ROM. the first 4-5 times I tried I thought could be the Rom was corrupted but I downloaded the OGD Rom from 2 different sources, from Sammobile and from that post, and always I tried to flash I had the same result. Then it was confirmed you can't go back in other XDA treat here in XDA you can see in the next link, in the first lines of text:

http://xdaforums.com/sprint-galaxy-note5/general/how-to-root-instructions-t3187895

I have tried all of these 2 posts:

this one

http://xdaforums.com/sprint-galaxy-note5/general/tutorial-enable-true-spark-lte-missing-t3191444

and this other

http://xdaforums.com/sprint-galaxy-note5/help/wifi-calling-t3183224

Detail 2:

When I download a stock firmware from sammobile I always choose the SPR code version of the ROM, and I never downloaded any ROM with XAS Product code version, so I think that's no the problem. I also will upload 2 set of captures from both N920P I have, showing the PhoneINFO app running in both phones and showing the CSC and other important information. All is exactly the same except actually the one with problems is running PD2 firmware and the the other that is running all with no problems has PC3 firmware.

Detail 3:

I have tried to get the original stock pre configuration with the CSC Select app you put below trying with PD2, PC3 and OK3 firmware and no luck with any of them. with Android 6.0.1 rooted (PD2 and PC3) the only comes back is the Sprint LTE Plus boot animation but no the hotspot. Also as told you previously, when I install an app to create a shortcut to go to the "hidden" hotspot native app the only I get is a blank and empty window as the first capture attached in starting this post, showing the hotspot app as if it would be disabled or something similar.

Detail 4:

When I try to install the "Sprint Zone 5.5.055.apk" it appears to get installed and the first time I try to open it, it ask for some permissions but at time to open the app stops getting an error and never running as if the phone has something that disable all Sprint features. So I don't understand what is happening with this phone. I'm not a developer but I have enough time working with my owns phones flashing firmwares with Odin since Galaxy S3 and this is the first time I see this. in the past any issue got solved just flashing an stock firmware and this include software issues, unroot process, or any other thing. All got solved in that way but with this phone nothing appears to work to recover it as the factory and I don't think could be any hardware issue because the rest of the phone works well and as described in the first of this post, these features I need work well with a custom Rom.