All sort of magic happens in BIOS, but after transition to 64bit, it should be fine.
The only problem is when BIOS programs some kind of hardware (usb), to write things into the memory like descriptors etc. and the hardware will overwrite portion of the memory.
This happens on some board with some versions of u-boot for ARM. There you should disable all the hardware devices before running your kernel, u-boot may be left the device enabled.
All sort of magic happens in BIOS, but after transition to 64bit, it should be fine.
The only problem is when BIOS programs some kind of hardware (usb), to write things into the memory like descriptors etc. and the hardware will overwrite portion of the memory.
This happens on some board with some versions of u-boot for ARM. There you should disable all the hardware devices before running your kernel, u-boot may be left the device enabled.