A method includes storing, on immutable memory, a first separately compiled portion of an OS, the first separately compiled portion having a first OS section including a patch hook having a patch lookup table address and associated with a first index value, and a second OS section including the patch hook associated with a second index value, storing, on mutable memory, a second separately compiled portion of the operating system, the second separately compiled portion including a patch lookup table at the patch lookup table address. The first and the second separately compiled portion are linked to form the OS. A determination is made that a change is required in the first OS section of the first separately compiled portion, resulting in updating the second separately compiled portion to include a first patch for the first OS section at a first patch address, and updating the patch lookup table.