a demo unit is a demo unit. You can't change that. You can't use regular custom firmware, nor original firmware, on this kind of Switch, without some firmware patch to make it like a retail one.
exFAt is bad because of data corruption. You can browse a lot (thousand) of threads about it.
Switch supports natively FAT32 (exFAT driver must be downloaded), this is the best way to use a microSD card
Except for a few exceptions, like big data patch to mod some games (I remember one specific game where the patch was bigger than 4GB), exFAT is useless and will slowly corrupt data.
exFAt is bad because of data corruption. You can browse a lot (thousand) of threads about it.
Switch supports natively FAT32 (exFAT driver must be downloaded), this is the best way to use a microSD card
Except for a few exceptions, like big data patch to mod some games (I remember one specific game where the patch was bigger than 4GB), exFAT is useless and will slowly corrupt data.