I finally got around to buying some of these little boards. (HY-TinySTM103T)
I know that @jcw at Jeelabs seems to use them a lot, and I was interested to see how well they were made and how small they are
Anyway, they arrived today, and seem to be quite a good board.
Whats puzzling me however at the moment, is that the board has some software pre-flashed onto it, which behaves as a 64k USB mass storage device.
I suspect that as the device is a STM32F103TB, and has 128K, that perhaps this 64k mass storage device is mapped to the upper 64k
But whether its intended to be used as an upload method I don't know yet as I need to solder on a header and connect my STLink and see if I can read back the entire flash (or just the bits that are not protected) and see if I can find where its putting the uploaded files.
I know I can just load the bootloader, but if possible I'll try to read out whatever code there is already in the device in case it comes in handy. But I suspect perhaps its going to be read protected, or perhaps its just got a mass storage demo loaded...