I'm a noob trying to find a solution to make a sd card write/read only? Like creating files is possible but to delete something you have to format the whole card. You only can delete everything or nothing. What are basic approaches to get there? Thanks for your help!
creating files is possible but to delete something you have to format the whole card.
That won't be possible with FAT16/32 or ExFAT filesystem. You have to re-write FAT and directory sectors to create new files.
There are special write-once cards for forensic purposes, but once written to they do not allow creating new files.