In a Linux system consisting of a bootloader, the kernel and an initramfs (no block devices, no other root filesystem):
Is it possible to make the initramfs read-only once expanded into memory?
SnapOverflow
In a Linux system consisting of a bootloader, the kernel and an initramfs (no block devices, no other root filesystem):
Is it possible to make the initramfs read-only once expanded into memory?
You could try giving the remount option a whirl.
Do pay heed to Zoredache's comment. Just because you can doesn't mean it won't go terribly, horribly wrong.