PROPRIETARY BSP
The BSP (Board Support Package) is that part of the SW that “overlaps” the kernel.
It adapts it to the specific HW programming target (an SBC or other). At this point , it is obvious that the “link” between the operating system and all the HW present on the board in question should be guaranteed as perfectly functioning in every detail, even the smallest which could be fundamental for a specific application (such as the RCT/CTS serial). Unfortunately it is rarely so in the industry.
With the typical BSPs you receive, the main peripherals definitely work, but that is about it. To find out the difference between the various boards we can try and see what happens if we “push it to the limit”, like with an FHD video at 60 FPS, or by simply using all the UART present in the system simultaneously. Have a go and see what happens.
And then ask for help … Panic !?
Yes. Often. This is why those who are in the business of selling (or producing) boards, often take the BSP, loads it onto their board and without too much ado or testing, sells the product. That is their goal, selling the HW. Make the sale, low level programming problems can be left to the end customer to sort out.