[Galaxy Tab S Q&A, Help & Troubleshooting] nigelstephens:
Edit. I managed to fix this and got it to work. The main problem was that my first window command had returned back with a prompt before I had time to complete the second window command. When I had the second window ready to hit return, I executed the first window command then imediately the second window command. It worked smoothly then extracting GB of data!

I have followed these instructions I found and they seem to work except the raw file resulting from them is 0 bytes. Any ideas?

I determined that my block for userdata is mmcblk0p21. All the commands in Cygwin return ok without problems. When in the second Cygwyn window and I do the nc 127.0.0.1 5555 | pv -i 0.5 > mmcblk0p21.raw the line returns no output back to the window other than the $ prompt.

I will paste the screen out put below these instructions I have followed.

The model is a Tab S SM-T800

1. Turn on your phone

2. Connect the phone in ADB mode

3. Unlock the screen.

4. Open a Cygwin terminal and enter (This assumes your BusyBox installation is at [/su/bin/busybox]. It may be at [/su/xbin/busybox]):

adb forward tcp:5555 tcp:5555

adb shell

su

/su/bin/busybox nc -l -p 5555 -e /su/bin/busybox dd if=/dev/block/mmcblk0p21

5. Open another Cygwin terminal and enter:

adb forward tcp:5555 tcp:5555

cd /nexus

nc 127.0.0.1 5555 | pv -i 0.5 > mmcblk0p21.raw

Screen output for the first window is.

Nigel@Philip ~

$ adb forward tcp:5555 tcp:5555

Nigel@Philip ~

$ adb shell

shell@chagallwifi:/ $ su

xbin/busybox nc -l -p 5555 -e /su/xbin/busybox dd if=/dev/block/mmcblk0p21 <

141|root@chagallwifi:/ #

Screen output for the second window is.

Nigel@Philip ~

$ adb forward tcp:5555 tcp:5555

Nigel@Philip ~

$ cd /samsung

Nigel@Philip /samsung

$ nc 127.0.0.1 5555 | pv -i 0.5 > mmcblk0p21.raw

Nigel@Philip /samsung

$

I'm scrathcing my head as It is not finding any data.

I got the mmcblk0p21 from the following.

Nigel@Philip ~

$ adb forward tcp:5555 tcp:5555

Nigel@Philip ~

$ adb shell

shell@chagallwifi:/ $ mount

rootfs / rootfs ro,seclabel,relatime 0 0

tmpfs /dev tmpfs rw,seclabel,nosuid,relatime,size=1420076k,nr_inodes=114328,mode=755 0 0

devpts /dev/pts devpts rw,seclabel,relatime,mode=600 0 0

proc /proc proc rw,relatime 0 0

sysfs /sys sysfs rw,seclabel,relatime 0 0

selinuxfs /sys/fs/selinux selinuxfs rw,relatime 0 0

/sys/kernel/debug /sys/kernel/debug debugfs rw,relatime 0 0

none /acct cgroup rw,relatime,cpuacct 0 0

none /sys/fs/cgroup tmpfs rw,seclabel,relatime,size=1420076k,nr_inodes=114328,mode=750,gid=1000 0 0

tmpfs /mnt tmpfs rw,seclabel,relatime,size=1420076k,nr_inodes=114328,mode=755,gid=1000 0 0

tmpfs /mnt/secure tmpfs rw,seclabel,relatime,size=1420076k,nr_inodes=114328,mode=700 0 0

tmpfs /mnt/secure/asec tmpfs rw,seclabel,relatime,size=1420076k,nr_inodes=114328,mode=700 0 0

none /dev/cpuctl cgroup rw,relatime,cpu 0 0

/dev/block/platform/dw_mmc.0/by-name/SYSTEM /system ext4 ro,seclabel,noatime,data=ordered 0 0

/dev/block/platform/dw_mmc.0/by-name/EFS /efs ext4 rw,seclabel,nosuid,nodev,noatime,discard,journal_checksum,journal_async_commit,noauto_da_alloc,data=ordered 0 0

/dev/block/platform/dw_mmc.0/by-name/CACHE /cache ext4 rw,seclabel,nosuid,nodev,noatime,discard,journal_checksum,journal_async_commit,noauto_da_alloc,data=ordered 0 0

/dev/block/platform/dw_mmc.0/by-name/USERDATA /data ext4 rw,seclabel,nosuid,nodev,noatime,discard,journal_checksum,journal_async_commit,noauto_da_alloc,data=ordered 0 0

/dev/block/platform/dw_mmc.0/by-name/PERSDATA /persdata/absolute ext4 rw,seclabel,nosuid,nodev,relatime,data=ordered 0 0

tmpfs /storage tmpfs rw,seclabel,relatime,size=1420076k,nr_inodes=114328,mode=755,gid=1000 0 0

/dev/block/loop0 /su ext4 rw,seclabel,noatime,data=ordered 0 0

/data/knox/tmp_sdcard /mnt/knox sdcardfs rw,seclabel,nosuid,nodev,relatime,mask=0077 0 0

/data/knox/sdcard /mnt/knox/default/knox-emulated sdcardfs rw,seclabel,nosuid,nodev,relatime,low_uid=1000,low_gid=1000,gid=1015,multi_user,mask=0006 0 0

/data/knox/sdcard /mnt/knox/read/knox-emulated sdcardfs rw,seclabel,nosuid,nodev,relatime,low_uid=1000,low_gid=1000,gid=9997,multi_user,mask=0027 0 0

/data/knox/sdcard /mnt/knox/write/knox-emulated sdcardfs rw,seclabel,nosuid,nodev,relatime,low_uid=1000,low_gid=1000,gid=9997,multi_user,mask=0007 0 0

/data/media /mnt/runtime/default/emulated sdcardfs rw,seclabel,nosuid,nodev,noexec,relatime,low_uid=1023,low_gid=1023,gid=1015,multi_user,mask=0006,reserved=20MB 0 0

/data/media /storage/emulated sdcardfs rw,seclabel,nosuid,nodev,noexec,relatime,low_uid=1023,low_gid=1023,gid=1015,multi_user,mask=0006,reserved=20MB 0 0

/data/media /mnt/runtime/read/emulated sdcardfs rw,seclabel,nosuid,nodev,noexec,relatime,low_uid=1023,low_gid=1023,gid=9997,multi_user,mask=0027,reserved=20MB 0 0

/data/media /mnt/runtime/write/emulated sdcardfs rw,seclabel,nosuid,nodev,noexec,relatime,low_uid=1023,low_gid=1023,gid=9997,multi_user,mask=0007,reserved=20MB 0 0

1|shell@chagallwifi:/ $ ls -al /dev/block/platform/dw_mmc.0/by-name

lrwxrwxrwx root root 2017-01-28 09:13 BOOT -> /dev/block/mmcblk0p9

lrwxrwxrwx root root 2017-01-28 09:13 BOTA0 -> /dev/block/mmcblk0p1

lrwxrwxrwx root root 2017-01-28 09:13 BOTA1 -> /dev/block/mmcblk0p2

lrwxrwxrwx root root 2017-01-28 09:13 CACHE -> /dev/block/mmcblk0p19

lrwxrwxrwx root root 2017-01-28 09:13 CARRIER -> /dev/block/mmcblk0p7

lrwxrwxrwx root root 2017-01-28 09:13 CDMA-RADIO -> /dev/block/mmcblk0p12

lrwxrwxrwx root root 2017-01-28 09:13 EFS -> /dev/block/mmcblk0p3

lrwxrwxrwx root root 2017-01-28 09:13 HIDDEN -> /dev/block/mmcblk0p20

lrwxrwxrwx root root 2017-01-28 09:13 OTA -> /dev/block/mmcblk0p11

lrwxrwxrwx root root 2017-01-28 09:13 PARAM -> /dev/block/mmcblk0p8

lrwxrwxrwx root root 2017-01-28 09:13 PERSDATA -> /dev/block/mmcblk0p16

lrwxrwxrwx root root 2017-01-28 09:13 RADIO -> /dev/block/mmcblk0p13

lrwxrwxrwx root root 2017-01-28 09:13 RECOVERY -> /dev/block/mmcblk0p10

lrwxrwxrwx root root 2017-01-28 09:13 RESERVED2 -> /dev/block/mmcblk0p17

lrwxrwxrwx root root 2017-01-28 09:13 SYSTEM -> /dev/block/mmcblk0p18

lrwxrwxrwx root root 2017-01-28 09:13 TDATA -> /dev/block/mmcblk0p15

lrwxrwxrwx root root 2017-01-28 09:13 TOMBSTONES -> /dev/block/mmcblk0p14

lrwxrwxrwx root root 2017-01-28 09:13 USERDATA -> /dev/block/mmcblk0p21

lrwxrwxrwx root root 2017-01-28 09:13 m9kefs1 -> /dev/block/mmcblk0p4

lrwxrwxrwx root root 2017-01-28 09:13 m9kefs2 -> /dev/block/mmcblk0p5

lrwxrwxrwx root root 2017-01-28 09:13 m9kefs3 -> /dev/block/mmcblk0p6

shell@chagallwifi:/ $