EFI implementation maps all memory read only

This is the likely cause for the page faults of other users. From a quick glance at bootboot.asm I think it does the same.

The loader should definitely map the core stack, the framebuffer and the cores data + bss segments writeable.

This would make the creation of a new page table very hard (unless the framebuffer is abused) because there is very little writeable memory available. (In fact a machine with <= 4 cores only gets 4KiB writeable memory, making it impossible unless memory is reserved in the binary)

Thus I propose that the loader also marks the page table writeable.