To create one 16 KiB-ROM out of 2 8 KiB ROMs, use the following method:

__Windows:__
Go to the CMD shell and there to the directory, where the 2 files are, which should be combined, then type:\\
\\
copy /b monkey.rom+basic.rom allinone16k.rom\\
\\
and the resulting rom file can be found in the same directory. Done. :-)\\

__Mac:__
Start application Terminal and then type cd and a blank. Drag the folder, in which the 2 files are, directly behind the blank. Check with typing ls -a, whether the 2 files can be seen. Then type:\\
\\
cat monkey.rom basic.rom > allinone16k.rom\\
\\
and the resulting rom file can be found in the same directory. Done. :-)\\