[PoP]

Very useful Thank you!

SSH log when run from the command line on my PW3 v5.8.7:

Spoiler:

[root@kindle root]# /mnt/us/unjail/mkbackup.sh

Copying partitioned area prefix.
33554432 bytes (32.0MB) copied, 3.888989 seconds, 8.2MB/s

Copying diag kernel block.
8388608 bytes (8.0MB) copied, 0.880231 seconds, 9.1MB/s

Copying main kernel block.
8388608 bytes (8.0MB) copied, 1.520744 seconds, 5.3MB/s

Extracting diagnostic uImage. 
2635032 bytes (2.5MB) copied, 0.163199 seconds, 15.4MB/s
Image Name:   Linux-3.0.35-lab126
Created:      Tue Sep 13 05:45:05 2016
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    2634968 Bytes = 2573.21 kB = 2.51 MB
Load Address: 80008000
Entry Point:  80008000

Extracting main uImage. 
2912456 bytes (2.8MB) copied, 0.195622 seconds, 14.2MB/s
Image Name:   Linux-3.0.35-lab126
Created:      Fri Nov 25 10:45:16 2016
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    2912392 Bytes = 2844.13 kB = 2.78 MB
Load Address: 80008000
Entry Point:  80008000

Copying main partition(2min).
471859200 bytes (450.0MB) copied, 148.702120 seconds, 3.0MB/s

Copying diag partition.
67108864 bytes (64.0MB) copied, 26.516923 seconds, 2.4MB/s

Copying local partition.
67108864 bytes (64.0MB) copied, 21.005913 seconds, 3.0MB/s

Copying boot0 partition.
2097152 bytes (2.0MB) copied, 2.982592 seconds, 686.7KB/s

Copying boot1 partition.
2097152 bytes (2.0MB) copied, 0.246512 seconds, 8.1MB/s
[root@kindle us]# ls -lh /mnt/us/backups
-rwxrwxrwx    1 root     root        2.0M Aug 23 12:52 boot0.bin
-rwxrwxrwx    1 root     root        2.0M Aug 23 12:52 boot1.bin
-rwxrwxrwx    1 root     root        2.5M Aug 23 12:49 diag-uImage
-rwxrwxrwx    1 root     root        8.0M Aug 23 12:49 diagkern.bin
-rwxrwxrwx    1 root     root       64.0M Aug 23 12:52 diagsys.bin
-rwxrwxrwx    1 root     root       64.0M Aug 23 12:52 localsys.bin
-rwxrwxrwx    1 root     root       13.6K Aug 23 12:49 main-config.gz
-rwxrwxrwx    1 root     root        2.8M Aug 23 12:49 main-uImage
-rwxrwxrwx    1 root     root        8.0M Aug 23 12:49 mainkern.bin
-rwxrwxrwx    1 root     root      450.0M Aug 23 12:52 mainsys.bin
-rwxrwxrwx    1 root     root       32.0M Aug 23 12:49 prefix.bin
[root@kindle us]# cd /mnt/us
[root@kindle us]# tar -czf backups.tar.gz backups
[root@kindle us]#