If you need downgrade/install other firmware, you could use the zero firmware or method listed on wiki.
Both ways have risk to harm TV...
Rewriting firmware?
Re: Rewriting firmware?
LE40B653T5W,UE40D6750,UE65Q8C
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]
DO NOT EVER INSTALL FIRMWARE UPGRADE
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]
DO NOT EVER INSTALL FIRMWARE UPGRADE
Re: Rewriting firmware?
You can try. Here is no chance to brick: either TV accepts firmware or don`t find any.
LE40B653T5W,UE40D6750,UE65Q8C
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]
DO NOT EVER INSTALL FIRMWARE UPGRADE
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]
DO NOT EVER INSTALL FIRMWARE UPGRADE
Re: Rewriting firmware?
Your goal is: will TV recognize firmware upgrade files on USB or not. You can decline further upgrade if you want.
But honestly i don`t believe this trick works. D series firmware files on usb have RSA signatures
But honestly i don`t believe this trick works. D series firmware files on usb have RSA signatures

LE40B653T5W,UE40D6750,UE65Q8C
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]
DO NOT EVER INSTALL FIRMWARE UPGRADE
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]
DO NOT EVER INSTALL FIRMWARE UPGRADE