Forced revert back to older firmware

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

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

# cd mtd_rwarea/
# ls -al Version.*
-rwxr-xr-x    1 root     0              44 Jan  1  1980 Version.1
# cat Version.1
SWU_T-CHL7DEUC_003000_I02_EK000DK000_100125
# touch Version.0
# ls -al Version.*
-rw-r--r--    1 root     0               0 Jan  1  1980 Version.0
-rwxr-xr-x    1 root     0              44 Jan  1  1980 Version.1
# chmod 755 Version.0
# ls -al 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
# echo SWU_T-CHL7DEUC_002004_I02_ES000DS000_090816 >Version.0
# cat Version.*
SWU_T-CHL7DEUC_002004_I02_EK000DK000_090816
SWU_T-CHL7DEUC_003000_I02_EK000DK000_100125
#

So after this, disabled "Alternative Firmware" selection became enable. So you can switch older firmware and patch some safe firmware on to latest firmware which has restrictions.

Thanks for ji035453 for his research.

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