SamyGO

yes, your firmware is 2004 now. lucky

get out from u-boot you could simple by entering "bootm"( without quotes) on prompt window (Leonid>)
or you can simple unplug TV to get out from uboot. it always works.
all those errors are Samsung related and common, don't trigger, it's ok.

from Top debug menu you can get out by entering last command (usually it is 99) but must look at the screen

It is ok, if you close putty connection while in TDM.

now you're secured and can flash patched firmware. important : if you get any error while patching - do not flash such firmware to TV.

good luck!

calvinyeoh wrote: 2nd thing is my firmware is T-CHL7DEUC but from your compatibility table it should be T-CHL7DAUC.

Judging from service menu screen shot, in fact, your firmware is (most likely): T-CHEAEAC 2004.2

sbav1 wrote: Judging from service menu screen shot, in fact, your firmware is (most likely): T-CHEAEAC 2004.2

Yes, you`re right! I did not paid enough attention and i was wrong. It most likely is T-CHEAEAC 2004.2.

Strange TV`s with strange firmwares...

But we have working u-boot and TDM and it is not the problem to restore TV if bricks. Just make dumps before to start.

yeah,
you have 50/50 chance to brick TV. But in this case you have high chance to repair it
I suggest you use T-CHEAEAC patched firmware for TV upgrade first, because with T-CHL7DEUC you had trouble.