Embed:
It has the same file name as "this working one", but its size is 103kB versus 21kB for the other.
We have to take that with a grain of salt, as the maximum size of the bootloader on the Mega2560 is 8K bytes (see datasheet, page 330).
The idea that a chip with 256 Kb of program memory would have a 103 Kb bootloader is, if I may say, laughable.