Okay everyone! It's been a while, but I have a real SOLUTION here. I have my phone now SER/SER/EGY and the ramadan is GONE and Samsung pay WORKS! It's the best of everything. No knox tripped, no funny bugs or anything since this is official firmware.
There is one requirement. I had to buy a russian SIM card for this to work. I paid 10 dollars on ebay, used a MegaFon SIM card as this uses the SER CSC code.
I followed T-shocks instructions again, plus a few changes. I'll go over what I did, and it changed the CSC for us with the multi-csc firmwares without the options to change it with other means.
Initially, just inserting the SIM card and rebooting does nothing. If you do that, it shows EGY/SER/EGY ( The last one can be ignored, thats what the phone originally shipped with and will never change)
Quoting
t-shock in a lot of these steps, as he was where I got all this info from mostly.
First I used
SamFirm to download my newest software. Under Model I put SM-G950FD and Region I put SER. Russia seems to have very little bloat, and also gets updates rather quick before some of the other regions I've noticed. Auto was checked, and I checked binary nature to to get it in parts. I kept Check CRC32 and decrypt automatically checked.
Once downloaded, I used winrar (or other program of choice to unzip) my files. I also went further in and extracted the pit file, which should be like DREAMLTE_EUR_OPEN.pit
Now MAKE SURE you have everything off your phone you want and backed up and INSERT THE RUSSIAN SIM CARD (or region card of your choice, just be sure to match download) I used Russia because samsung pay works and also accepted my american credit card in the app.
Go into download mode, Power, Vol Down, Bixby button at same time.
Open ODIN and put the BL file to the BL option in Odin
AP file to AP option
CP file to CP option
and CSC (NOT HOME_CSC) at the CSC file
Pit file under the pit tab
Check your options and Do Not select repartition, especially if you're already on a OXM multi-csc firmware. For some reason mine was checked, so I unchecked it.
Once you're ready and see it connected to PC properly, start the flash.
When done, it will start the regular boot process, blue screen with android robot doing some work, etc, and you'll get the the welcome screen. Shortly after you will get a screen about having a new SIM card and will ask you to restart phone to apply new SIM card settings. This is important for this to work! Go ahead and accept, and it will do a factory reset. It will show russian characters and you'll have no clue what it says lol. But give it a little, and you'll be back at the welcome screen, in Russian. Just select your language from the dropdown and everything will be back to normal. You can go ahead from there, set up your phone how you want, and you'll also see the new CSC info at that time
I powered down, inserted my US straight talk SIM and went about my business. It didn't want me to reboot again for anything, just worked for me. I'm assuming because the US SIM card doesn't assign a CSC to the internation DUOS version that it works this way. Because the russian SIM card has a csc in the multi csc it asks to change.
You'll now have a fresh installed ROM, should hopefully get updates as they are rolled out, and have a new region
Samsung pay works and no more Ramadan stuff in my calendar. The samsung pay app won't have the american rewards and stuff and has Russian advertisements, but everything important like adding your card is in english.
I want to thank
t-shock again for all your help and links that you helped out with.