Ok, will try again in the next days. Really strange problem with that unresponsive call screen, was unable to reproduce but happened regularly, tried many cpu settings etc (maybe it was caused by the upcoming USB soft brick I had a few days later*).
Will see if it's gone now, chances are good I guess when people don't report it anymore.
*offtopic (soft usb brick)
managed to get it undone with the threads here on xda, but what I wanted is to ask, is what can cause this? found many threads how to solve (was not that hard, but still needed some time to do), but nowhere was pointed out how this can happen to legend, or I overlooked it
Just interested.... don't know if it matters - phone is s-off with an xtc-clip before htc released their unlocking tool.