but found that the connection is extremely noisy.
often the movement of me putting down the phone on the table is enough
to break the upload.
i had a similar problem with an unconnected input pin which caused a
reset of a microcontroller, just by moving some centimeters in a
distance of one meter. check if you have left unconnected input pins on
your USB converter. what about hardware flow control input? (RTS/CTR)
andreas