Long story short, on my board I want to trace my Linux kernel using Coresight. Unfortunately, to allow the PTMs to trace through the kernel, SPNIDEN (Secure PL1 Non-Invasive Debug ENable, see ARMv7 ARM p2075) must be set high. I would like to do so from the bootloader (eg. without a JTAG device attached), and I'm only guessing that this is a value controlled by a fuse. Is this true? And if so, what parameters do I need to override this fuse from U-Boot?