Int 67 Fn 5DE4 - Rm386 - Set Write-protection For Page In First Megabyte [m] AX = 5DE4h BL = page number BH = access (00h read-only, 01h read-write) Note: RM386 traps this functions on the initial transition to protected mode caused by the INT instruction, which means it can not be overridden simply by hooking the interrupt