Syslinux - May 2011 - grub config garbage after 512 bytes when chainloading via chain.c32

[back story]: I want to convert a non-iso customized Solaris install 
image (for USB flash stick) to an isolinux hybridized bootable iso image 
... since the Solaris installer uses grub out of the box, my first 
approach was to chain load grub from isolinux (this isn't strictly 
material to the problem, just trying to avoid the "why on earth would 
you do that?" responses ;-)  I've smoke-tested converting the grub 
config into an isolinux config so I can just cut grub out entirely, so 
the grub problem will probably become academic, but I still wanted to 
raise it ...

[grub issue]: the chain loading of grub (legacy) stage2 works fine, but 
it only displays the first two of four menu options that I have in my 
menu.lst.  Dropping to the command interface and catting the menu.lst 
shows that the file appears to be corrupted or possibly concatenated 
with a sector from another file, starting after the 512th byte (which 
falls in the middle of the third 'title' line).  I get the same behavior
with either stage2 or stage2_eltorito (at first I hoped it just needed 
the eltorito version because it's an iso9660 fs).  The menu.lst file 
appears contiguous in the iso image (which I'd expect, since it's <
2048
bytes), and catting it in the grub shell prints exactly the right number 
of chars, but most of it after byte 512 shows as '?' (assuming these are
unprintable ascii).  I found what I think is the "garbage" elsewhere
in
the image, and if I'm translating back to the address that would appear 
in the iso9660 file descriptor table, it's the beginning of the grub 
reiserfs_stage1_5 file ... for whatever that's worth.

any idea what's going on here?

-g

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