so i presume you are on e-1.15-q-20230914331056-dev-starlte
i do not have the same device so i have not encountred the same situation.
general advises are :
- save (copy-paste) the content of “internal storage” on a microSDcard or on your computer
could be usefull if during the process you will be forced to format /data (including the internal storage content) - if TWRP is présent on your device, make a backup of all partitions
/data (except the internal storage content) will be usefull if during the process you will be forced to wipe /data (except the internal storage content) or format /data (including the internal storage content)
/system will be usefull if you want (need) to restore your device at its actual state (e-1.15-q + your apps & settings) - also read and follow https://doc.e.foundation/support-topics/backup-and-restore-ephone.html
Check if you have already latest Samsung firmware installed by compare your baseband version
(viewable in → settings → about the phone → android version 10 → baseband version)
latest is G960FXXUHFVG4, builded date 2022-07-22 vendor secutity patch date 2022-03-01
if not, go to SM-G960F/XEF/G960FXXUHFVG4 (french free from carrier)
other countries : https://samfw.com/firmware/SM-G960F
disable security code or gesture at boot
then you can go with latest e-1.21-t, intermediate versions are not usefull
first try a “dirty flash” (without wiping anything)
you can go direct to step (8) or (9) BUT WITHOUT WIPING OR FORMAT ANYTHING ( no factory-reset)
Please share feedback…