How to recreate the 31 July color.com

Hello,

I should be most grateful if anyone could show me my error. 

I am trying to recreate color.com using boot.asm, color.asm and gen.asm 
from http://colorforth.cvs.sourceforge.net/colorforth/colorforth/masm/ 
and color.com from 
http://colorforth.cvs.sourceforge.net/colorforth/colorforth/ and I have 
not made any changes to the files.

I am following these steps:
Assemble and link the source code using MASM with the command line "ml 
/AT /Fl /Sg color.asm".  This produces a 18,432 byte file.
I then open the original color.com file (64,512 bytes) and overwrite the 
first 18,432 bytes with those that I have just assembled.

This new color.com does not work--it displays the coloured squares of 
the logo but nothing else and the computer becomes unresponsive.

My understanding was that everything after the first 18 blocks (first 
18,432 bytes) is written in colorForth, and everything before comes from 
the assembly code.  There do seem to be some small differences in the 
files up to byte 12,347, but after this point the original file is 
mostly non-zero values whereas the assembled one is just padded with 
zeros, so I think I am overlooking something fundamental.

Regards,
Jason