@robert-hh Concurrent access was my first idea too. To test it: I erased the flash to standard boot and main. Then I preloaded the SD with data. Re-ran the FTP test and it still had the same crashes. Using the FTP server on the device is for me is the easiest way. Otherwise I would need to create a Timer to upload data at regular intervals. To keep data transfer low I would need keep the intervals long avoiding me to have the flexibility of choosing which data I want to download and when. To be honest, I'm a bit disappointed by the eagerness of pycom to attack this problem. The same with my other crash report.

@paul12345 : I do not know why the implementation is recursive. Maybe it always was, or it's the most elegant solution. About the double quote: No, it does not work on WiPy if you drop the double quote at the end of the search string. But you will have a match on machines with more memory, simply because the sample string (line) you are searching at does not contain the pattern mp3". B.T.W.: Shortening the string in line works on WiPy. Regards, Robert