SparkFun IoT RedBoard max storage capacity of microsd card

what is the max memory storage capacity of the microSD Socket for the SparkFun IoT RedBoard ?
if it is 32GB or less, then is there a way to expand it to 256GB?

Yes, the practical limit is 32gb…there are backdoor options to use exFAT with IDF but you have to build custom firmware and we don’t have any advice for such

Curious, FAT32 is good to 4GB so why can’t the Redboard go to 4GB?

It can…but not with a single write to a file (you are subject to the amount of memory on the IoT Redboard for any single write)

But you should be able to log many small files, often