But if you already have an SFS partition and then change the DOSType identifier to something else, then a matching filesystem for the partition will not be found in the RDB. You would have to change the identifier back, or reformat it with the new one. I did this once with SFS and the partition changed to NDOS. When I changed the identifier back, it started working again.
Well, isn't it quite obvious you're supposed to add the filesystem with the new DosType aswell? Naturally if you're just changing the dostype, add the very same filesystem, just use the new dostype value you want to use. Then change all partitions to use the new filesystem (dostype). Check that everything is fine, and then remove the old filesystem.
There is no need to reformat at any point. The key here is that you use the very same filesystem, just different dostypes.
In fact you can even do this in the reverse order: First change the partitions to use the new dostype, and only then add the filesystem with the matching dostype. In this case you get NDOS partitions temporarily, though.
All bets are off if you use different, incompatible version of the filesystem for the new dostype. If it's not compatible you need to format, of course.
