After a long thinking i've decided to create a root or jailbreak tool for LG's awesome webOS, today am stating this thread to release this new root tool, but before that! am gonna ask you for some logs from webOS 3.5 and lower.
Everyone in this thread must know about webOS if not do your homework then get back again, LG did a great work on this operating system after HP and Palm's versions. they even supported Raspberry Pi module B. but webOS OSE aka Open Source Edition is really different from TV's version.
LG think about Security and frequently release updates that doesn't have anything new except some patches to close down known holes, one of my favorites was a directory traversal that can replace in tv files and binaries during install (partially closed recently).
let'stake a look at LG's partition filesystem types, on tv's they chooses to use ext4 for writable partitions (/var, some of /mnt/lg/*, /home and /media) everything else is using squashfs which is a read only compressed filesystem you cannot modify it.
If you can dump the squashfs partition unshquash it then recompress you will face another problem of hashes and crc checks (checkout the update binary for more details) if you dd it back to block device without kernel and/or bootloader patches. so this is not gonna just work easily.
What we can really do it play on the RW parts of the system, one of the design flaws on webOS is the devmode aka Developer Mode, they ship it in a Read Write partition so that's easy to be modified.
To do that you must have root access or some powerful exploits to achieve your goal.
This method is using memory access vulnerability to get root and then jailbreak the tv. i ported some parts of the other root thread even if some are not even needed.
To jailbreak connect to your tv via prisoner user after uploading GetMeIn binary into it then :
chmod +x GetMeIn ./GetMeIn
mkdir -p /media/cryptofs/root/etc mkdir -p /media/cryptofs/root/lib
there is some old pictures attached, i did some modifications after those.
Hope this is good enough.