Small typo:

    --- before      2018-01-31 17:12:13.626560688 -0800
    +++ after       2018-01-31 17:12:17.494580179 -0800
    @@ -1 +1 @@
    -uint32_t buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
    +uint32_t *buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);