Daniel 
Okay, there have been many discussions about illegal instruction errors, segmentation faults and so on, but i've got a somewhat different behaviour. I already tried disabling optimizations ( -O0 ) , passing Flags like "-D__GGC_FLOAT_NOT_NEEDED" and so on. Since the FriendlyARM-Toolchain is configured with "--with-arch=armv4t" or "--with-tune=920t" etc. , there is no need to pass Flags like "-march" " and similar flags. I made a Qt application. It starts without errors and works fine. I can do some floating point operations too without problems. But when I close the app ( a button is connected to the QApplications quit()-slot ) , I get a illegal instruction or segmentation fault error. Sometimes the application does not quit, but hangs with a green screen too. Some information, that might be useful: i'm running an Angstrom console image with Qt and tslib installed by myself. I use the toolchain from FriendlyARM ( http://www.friendlyarm.net/dl.php?file=arm-linux-gcc-4.4.3.tgz ) and copied the libstd++6 from that toolchain to my mini2440.