SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world.
And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download two short videos (registration required) highlighting:

System Workbench for STM32

Debug stays at Reset_Handler, step into/over buttons are disabled

their are some thread here and how to on the net for rtos aware debug.

you need to add a line on the openocd cfg
add a variable in your code (free rtos compat) for debugger to catch it
and voila.

likley your reset problem was h/w or that reset cfg.

i personaly used nucleo,discovery and a few custom baord with standard openocd cfg and almost never change configuration.