made so that 1st boot jumps to flash if button not pressed, ie bootloader activates with button pressed when reset
modified 2nd stage bootloader :
 - can effectlively flash to chip the selected file (asynchronous flash writng / file reading from microsd / erasing to let the video frames be displayed smoothly and progress be displayed)
 - upgraded to new USB API, using it from memory
 - many bugfixes
 - selection
 - XBM 128x128 B&W icon reading from uSD (not selected automatically, keeps using bitbox icon now)
modified test kernel to handle new API