[root@fnas-test /mnt/main/.freenas]# dd if=firmware.img of=/dev/ada0s1 bs=128k
14025+1 records in
14025+1 records out
1838301696 bytes transferred in 18.365129 secs (100097402 bytes/sec)
[root@fnas-test /mnt/main/.freenas]# fsck_ffs -n /dev/ada0s1a
** /dev/ada0s1a (NO WRITE)
** Last Mounted on /usr/local/freenas/os-base/amd64/_.mnt
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Cyl groups
39483 files, 1362870 used, 2167462 free (3542 frags, 270490 blocks, 0.1% fragmentation)
[root@fnas-test /mnt/main/.freenas]# dd if=/dev/urandom of=/dev/ada0s1 bs=128k
dd: /dev/ada0s1: short write on character device
dd: /dev/ada0s1: end of device
14026+0 records in
14025+1 records out
1838301696 bytes transferred in 45.677954 secs (40244834 bytes/sec)
[root@fnas-test /mnt/main/.freenas]# dd if=firmware.img of=/dev/ada0s1 bs=128k conv=sparse
dd: /dev/ada0s1: Invalid argument
14025+1 records in
14025+0 records out
1838284800 bytes transferred in 10.007447 secs (183691685 bytes/sec)
[root@fnas-test /mnt/main/.freenas]# fsck_ffs -n /dev/ada0s1a
** /dev/ada0s1a (NO WRITE)
** Last Mounted on /usr/local/freenas/os-base/amd64/_.mnt
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
DIRECTORY CORRUPTED  I=225216  OWNER=root MODE=40755
SIZE=512 MTIME=Sep 19 10:39 2014
DIR=?

UNEXPECTED SOFT UPDATE INCONSISTENCY

SALVAGE? no

MISSING '.'  I=225216  OWNER=root MODE=40755
SIZE=512 MTIME=Sep 19 10:39 2014
DIR=?

UNEXPECTED SOFT UPDATE INCONSISTENCY

FIX? no

MISSING '..'  I=225216  OWNER=root MODE=40755
SIZE=512 MTIME=Sep 19 10:39 2014
DIR=/usr/local/lib/python2.7/site-packages/django/contrib/redirects/locale/id/LC_MESSAGES

UNEXPECTED SOFT UPDATE INCONSISTENCY

FIX? no

** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
UNREF FILE  I=225217  OWNER=root MODE=100644
SIZE=1031 MTIME=Dec 12 20:37 2013
RECONNECT? no


CLEAR? no

** Phase 5 - Check Cyl groups
39483 files, 1362870 used, 2167462 free (3542 frags, 270490 blocks, 0.1% fragmentation)