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Old 05-06-2015, 07:29 AM   #1
telemark
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Join Date: Nov 2013
Posts: 1,503
Howto: Backup Roamio SW update from HDD (root/kernel)

YMMV, but this worked for me. Before the software update is installed on flash, it's stored on disk in MFS. Even with a lack of MFS tools, the SW update can be located using traditional data recovery techniques, bypassing the filesystem.

I don't know when it's deleted, but it would have to be on disk at least when "Pending Restart".

Hardware used:
PC
Sata dock
Roamio HDD

Software used:
Linux*
PhotoRec
pmdmp

1) Get partition offsets, and isolate MFS app partition(s)
# pmdmp-static /dev/sdX
a) copy & paste the line with #10 MFS app region:
# losetup -f /dev/sdX --offset 180486095872 --sizelimit 838860800
or b) Use a Roamio aware linux kernel
or c) Use a Mac w/OS X (Premiere only)
or d) tivopart (Premiere only)

2)
Grab, install, run photorec on MFS app partition(s)
# photorec /dev/loop0

3) Test integrity of all recovered gzip fragments.
# ls recup_dir*/*.gz | xargs -n1 zcat > /dev/null
You're looking for lines that look like:
gzip: recup_dir.2/f0998559.gz: decompression OK, trailing garbage ignored

4) Extract it
zcat recup_dir.2/f0998559.gz > f0998559.bin

5) Check file type
# file f0998559.bin

Options are:
f0998559.bin: ASCII cpio archive (SVR4 with CRC)
or
f0998559.bin: Squashfs filesystem, little endian, version 4.0, 320783588 bytes...

The first example would be a kernel or root filesystem fragment when built piecemeal.
The second example would be a complete root filesystem image.

6a) If cpio, Extract
Code:
# cpio ... f0998559.bin
# ls -la
-rw-r--r--  1 root root      89 May  6 06:52 .jpminstall
-rw-r--r--  1 root root 4537336 May  6 06:52 vmlinux.px
6b) If squashfs, Mount root filesystem and take a look around
Code:
# mount -oro f0998559.bin /mnt/
# ls /mnt
bin     db   dist  fuse    install  mnt  platform  product  sys  tvbin  tvres  var
cgroup  dev  etc   initrd  lib      opt  proc      sbin     tmp  tvlib  usr    volatile
* More options:
PhotoRec exists for Win / Mac / Linux.
Whether the OS can get at the partition map will determine whether you have to scan MB's vs the whole drive.

** To run against MFS app 2, use partition #12 and
# photorec /dev/loop1


Last edited by telemark; 05-13-2015 at 01:13 PM.
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