DD dump and then searching for pool_guid in hex

[130]EOFL@freenas:~$ gpart show da0
=>        40  7814037088  da0  GPT  (3.6T)
          40          88       - free -  (44K)
         128  7814036992    1  freebsd-zfs  (3.6T)
  7814037120           8       - free -  (4.0K)

EOFL@freenas:~$ sudo dd if=/dev/da0 of=~/da0lastsectors.bin skip=7814036000
Password:
1168+0 records in
1168+0 records out
598016 bytes transferred in 15.721707 secs (38038 bytes/sec)

#This is the actual good pool (on partition 1)
EOFL@freenas:~$ sudo zdb -l /dev/da0p1
------------------------------------
LABEL 0
------------------------------------
    version: 5000
    name: 'RaidZ-4TBx3'
    state: 0
    txg: 13958374
    pool_guid: 3025141855217507971          <-------------

#Convert to hex
3025141855217507971 == 29fb767d4b67de83

#run xxd (linux) or hd (BSD) = (hexdump)
EOFL@freenas:~$ xxd da0lastsectors.bin
000010a0: 0000 0028 0000 0009 706f 6f6c 5f67 7569  ...(....pool_gui
000010b0: 6400 0000 0000 0008 0000 0001 29fb 767d  d...........).v}       <--- 29fb 767d
000010c0: 4b67 de83 0000 0024 0000 0020 0000 0006  Kg.....$... ....       <--- 4b67 de83

#GUID = last 2 bytes of line2, first 2 of line 3.

#This is the broken remnant pool (with the same name) (on wholedisk/mbr?)
EOFL@freenas:~$ sudo zdb -l /dev/da0
------------------------------------
LABEL 0
------------------------------------
failed to unpack label 0
------------------------------------
LABEL 1
------------------------------------
failed to unpack label 1
------------------------------------
LABEL 2
------------------------------------
    version: 5000
    name: 'RaidZ-4TBx3'
    state: 2
    txg: 162
    pool_guid: 1085295563579971048          <-------------

#Convert to hex
1085295563579971048 == F0FBE909F7DD5E8 == 0f0f be90 9f7d d5e8 (leading zero)

# FOUND! at the very beginning of the sector dump. (grep for "0f0f be90" or other pairs, may be newline/split)
# manually translate hex to sector numbers/offsets.
# manually erased with targeted dd ~4 sectors. (real pool has to be exported first because ZFS locks the dev)