Trumany, thanks for the link, but I don’t think I was clear with my initial question.
I have a requirement to have a read-only system, with all writes physically disabled (not just through the OS, or by mounting the drive as read-only, etc).
An SD card provides me with half of the answer, with a physical write protect switch allowing me to update the OS when I need to, but keeping the system locked down otherwise.
But there’s no physical write-protect switch on the eMMC, so I’m looking for a way to permanently lock it down or disable it. Most modern eMMCs have a flag you can set to permanantly write-lock it, say over JTAG. I’m trying to see if anyone has tried that before with a Tx1, or even knows where to start.