Or you could forego DMA completely if you wanted. Almost all DMA capable devices have some kind of non-DMA route to access the data. It may be slower and it wou

Or you could forego DMA completely if you wanted. Almost all DMA capable devices have some kind of non-DMA route to access the data. It may be slower and it would of course still enable an adversary with access to your hardware to replace the device you boot from with one that has compromised data on it. But at that level it is usually game over anyway. I was thinking of just using an SD card, and if you're really paranoid about this (which I am!) you could glue it into the slot or make it physically impossible to replace it without damage to the case.