A very reliable source, though it requires registration to download files [3].
The TV might display an upside-down picture or incorrect colors (negative image).
Download the EEPROM or SPI Flash dump for the Samsung UA40H4200AR Download dump samsung ua40h4200ar rar
Here is a curated guide and interesting technical context regarding this process. Where to Download (RAR File)
The TV turns on, shows the "Samsung" logo, and then immediately restarts. A very reliable source, though it requires registration
Before flashing, always back up your original, corrupted firmware. Interesting Technical Insight: Why the Dump Fails UA40H4200AR
Frequently hosts Samsung firmware dumps for flash programmers [2]. A very reliable source
Enter the Service Menu ( Info -> Menu -> Mute -> Power on standby) and adjust the LVDS Format or Option Byte settings to match your specific panel model [4].