[M100] Writing binary files from BASIC

[B 9]

I was attempting to write a binary data file using BASIC's OPEN and PRINT #
commands and found that there are three bytes that are not allowed: 0, 26,
and 127. I had expected CHR$(26) might be a problem as that is the End Of
File character, but the other two were a surprise. Is this limitation
documented somewhere? It's not in the BASIC manual from Radio Shack.

Here's an example of what doesn't work:

 10 open "foo.do" for output as #1
 20 for t=0 to 255
 30 print #1, chr$(t);
 40 next t
 50 close #1
 80 open "foo.do" for input as #1
 90 x=0
100 if eof(1) then 200
110 c = asc(input$(1,1))
120 if c<>x then print x
130 x=c+1
140 goto 100 h
200 close #1
210 end

I can think of various workarounds, but they are ugly. What is the best way
to write binary files with arbitrary data from BASIC on a Model T?

Thanks for any guidance.

—b9