Firmware files for these boards are often large (over 300MB) and are split into multiple parts (part1, part2, part3) by technicians on repair forums like Televid-Sib to meet upload limits.
Plug the TV back into the power outlet while continuing to hold the Power button. Download CV338H A42 1366x768 SamsungIR part3 rar
You cannot extract "part3.rar" by itself. You must download all parts (usually 1 through 3 or 4) into the same folder and extract the first part to reconstruct the complete firmware file. Installation Steps (USB Method) Firmware files for these boards are often large