even if FAT32 is recommended, a simple stick formatted with something else should not freeze the scope ...
It is not just only "recommended".
It is absolutely mandatory to use native FAT32.
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What makes an engineer put something other than what the manufacturer says is compatible in that hole. Nevertheless, even if mechanical compatibility exists.
There are three things. Mechanical compatibility. Electronic compatibility. These two are called as HW compatibility.
In addition to these, there will be SW compatibility.
All of these three conditions must be true togehter (AND). Only when all conditions are true then insert it in hole.
Should measuring devices, designed for trained engineers and technicians, also have so-called "blonde compatibility": Put anything in the hole and everything will work, or at least not lose consciousness.