SamyGO

We don't know until you try

Also it's weird that our compatibility table has higher firmware than latest
LE26C350D1W LCD TV T-MSX5DEUC 2005.4
I think something corrupted...
What is your current fw?
It's up to you to update it or not.
But if you try, please let us know about your result.

I think first and third one is same firmware. Just look like duplicate...
And you cannot install TDT (trident based) firmware.
Which allows much programs and Xorg on it.

Returning to older firmware might be possible but we do not know actually.
If samsung disable it, you cannot revert it by TV menus. You needed to use ExLink port.