Forced revert back to older firmware

This procedure for reverting back to older firmware can help you if you upgraded TV to latest firmware accidentally.

But if your new TV comes with latest firmware already, this instruction cannot change anything for your TV...

Enabling Telnet

With the latest firmware, Samsung disabled both Ex-Link console connection and external applications probably to stopping us. So you cannot create telnet connection to TV because you cannot use Telnet Enabler application. If you copied Telnet Application to TV's flash memory before you are lucky. But if you not, please don't cry, here is the solution.

Trojan Horse

Historicaly : Trojan is a giant horse that has hidden soldiers in it, it was used first at Troya A.D.2500-3000, which is in Çanakkale, Turkey now. Soldiers leave a huge wooden horse behind as a gift and fade away... Enemies take that giant horse inside of city walls. But when night comes, hidden soldiers that in the horse get out and open the gates... :)

So we follow the same pattern here. Delete a some content library tool, something like "children stories" than download new one from Samsung and use downloaded file as Trojan horse. After downloading file, place SamyGO Telnet Enabler folder to inside it, then move files to USB and plug in to TV. After copy to TV's Flash, you can run Telnet Enabler from Content Library that enables Telnet (or open the gates :) )

Forcing to Enable Alternative Firmware

After some firmware upgrades, Samsung doesn't let us revert firmware back to older state. Actually we were using as a solution for that, flashing mtd_exe and mtd_appdata partitions via manual flashing from telnet connection, enabled via telnet application.

Instead of flashing dump of older firmware to actually used partition (which is risky), we can switch to older firmware via this hack. This way is more safe than other approach. Lines bellow will make TV use alternative firmware.

Notice: This output/lines for B650-B750 devices, so firmware name contains T-CHL7DEUC, for other TV's you need to use corresponding strings and versions!!!.

localhost login: root
-sh: id: not found
# cd mtd_rwarea/
# ls -l Version.*
-rwxr-xr-x    1 root     0              44 Jan  1  1980 Version.1
# cat Version.1
SWU_T-CHL7DEUC_003000_I02_EK000DK000_100125
# echo SWU_T-CHL7DEUC_002004_I02_ES000DS000_090816 > Version.0
# ls -l Version.*
-rwxr-xr-x    1 root     0              44 Jan  1 00:00 Version.0
-rwxr-xr-x    1 root     0              44 Jan  1  1980 Version.1
# cat Version.*
SWU_T-CHL7DEUC_002004_I02_ES000DS000_090816
SWU_T-CHL7DEUC_003000_I02_EK000DK000_100125
#

So after this, disabled "Alternative Firmware" selection becames again enabled. So you can switch to an older firmware and patch some safe firmware over latest firmware which has restrictions.

Thanks for ji035453 for his research.

--Erdem_ua 02:52, 23 April 2010 (EET)