ERROR: Unable to write file : DISK_ERR, leads to Out of Memory errors.

Actually you can trace this down really easily:

var t = getTime();
while (true) {
  var p = getTime();
  if (p<t) console.log("Backwards! "+p+" vs "+t);
  t=p;
}

I think this is probably a SysTick-based problem again. I need to add some code to detect the case where the SysTick timer overflows but there is no interrupt in time. It shouldn't even happen - but it seems it does :(