We don`t have any modified firmware for C and D series. Feature you`re asking for might could be switched to on by changing model in service menu. But i don`t know if your TV supports it at all.
Use it on your own responsibility, you could brick your TV as easy as switch Video support too. 50/50.
Samsung D503 doesn't play video from USB
Re: Samsung D503 doesn't play video from USB
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: Samsung D503 doesn't play video from USB
Is your front touch pannel working after you`ve changed model?
Info must be moved to our wiki, could you? Thanks
Info must be moved to our wiki, could you? Thanks

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