Second problem :
in fact it happens only if yoiu connect two power source in the mean time ie : jst plug + serial port … then the RTC clock seems to stay at the time it was at this moment forever (untill you set it another time to another date and everything works fine again) …
solution : unplug jst power BEFORE using serial plug. and same thing when plugging the JST : remove the serial connector BEFORE.
no solutions for the two other problems at the moment.