Hm then the firmware binary overlaps with with that memory region?
In any case I think the best course of action would be to open an issue at Zephyr (Issues · zephyrproject-rtos/zephyr · GitHub) and have them implement the functionality of including files in partition, building that partition binary and including it in the final output binary, then it’s pretty much automatically in PlatformIO with the next update, because PlatformIO just calls into Zephyr’s (cmake) build system. If it needs additional implementation on the PlatformIO side, a issue in GitHub - platformio/platform-ststm32: ST STM32: development platform for PlatformIO should be opened.