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

STM32429I_Discovery board with printf float support problem

Do you use RTOS? I have had the same effect. -u _printf_float seems only to work without RTOS.
The effect seems to be a faulty malloc heap overflow check in syscall.c
printf(“%f”) uses malloc. With RTOS, malloc does not return any memory and printf continues with a null pointer.
See this topic https://www.openstm32.org/forumthread353Question