WMXZ

I use MTP.reset() when informing PC to reset the MTP connection. This is useful when Teensy is writing to disk while connected to PC, as PC will not be aware of new files and will never enquire. There are multiple ways of informing PC that...

yes, for example a dual microSD card reader will show up as two devices, even without SD card inserted

Or your use (cabling,etc) of the RTC battery

I have frequently used 1TB SD cards formatted with a PC (exFAT)

I noticed (on T4.1) similar missing early print statements where I was waiting for serial to come up and printed some text that never showed up. In the end it turned out, that the Win PC (in my case, not Mac) enumerated USB so that Serial was...