Tried to halt the application and found the problem. And see there was a HW Error. Apparently we twisted 5 of the chip pins in our layout. Changed it manually and it works. Also the low level clock was not included in the design, so some addictional changes in the mcuconf were necessary. Now it works as expected.
Thanks for the help!
Gabriel
STM32F746IGT OpenOCD Problems
Moderator: RoccoMarco