SPARC64_BOOT_BLOCK_OFFSET
rv = pread(params->fsfd, &bb, sizeof(bb), SPARC64_BOOT_BLOCK_OFFSET);
rv = pwrite(params->fsfd, &bb, sizeof(bb), SPARC64_BOOT_BLOCK_OFFSET);
SPARC64_BOOT_BLOCK_OFFSET / SPARC64_BOOT_BLOCK_BLOCKSIZE);
SPARC64_BOOT_BLOCK_OFFSET);