i was on XFV ORIGINALLY (VODACOM)
Got a "bee" in my "bonnet "
I flashed a French firmware XEF
eg i had XEF/XEF/XFV
It worthwhile to note that 3rd code CSC is hardcore. You cannot change it.
Then i did not have volte etc and i wanted to return to XFV Firmware.
I tried flashing XFE firmware (factory reset etc) (Why i don't know anyway.)
I now had CSC XFE/XFE/XFV
I then decided to flash latest Vodacom firmware
XFV, factory reset and landed back on
XFV/XFV/XFV
Started getting OTA 's again!
You know that you must flash 4 of the 5 files
In correctly designated slots in Odin.
Remember you have to factory reset.
Also if unzipping firmware
HOME _CSC_OXF your data stays intact (dirty flash)
You have to choose CSC_OXM plus the other 3 files in Odin This way you phone will be factory resetted.
Also i just checked with Samfirm and eg Vodacom latest firmware is showing.!
See screenshot. for example.
If you on MTN then just follow same as above (if you want to but with MTN Firmware.
Good luck
post note
i just remembered,
when my Samfirm software was not picking up latest Firmware updates reason was that i was using old Samfirm v0.3.1 ,instead of latest Samfirm v0.3.6
Download Samfirm from XDA '
https://forum.xda-developers.com/galaxy-tab-s/general/tool-samfirm-samsung-firmware-t2988647
View attachment 543467