Creating a FreeDOS bootdisk on OS X

The BIOS on my Promise Ultra133 TX2 IDE card is a version not listed on the Promise support site (2.20.0050.10). So it seemed sensible to update to something half-recent (2003 - 2.20.0.15 *crazy versioning scheme*). Of course such an upgrade requires a DOS bootdisk. The 2 floppies I found in my room are >5 yrs old, and refused to play ball. So how hard could it be to make a Boot-CD -- on my CD-burning machine, a Mac?! *sigh* Several coasters later...

Anyone else banging their head against BIOS-hell:

[You need to go through this as .iso images are read-only.]
1) Download a FreeDOS disk image -- we just need the floppy boot image, in this case named fdboot.img.
2) Create a directory [cd-dir], and place this boot-disk image into it.
3) Add the DOS BIOS flash utility and anything else you need to [cd-dir].
4) In the terminal:
cd [cd-dir]
hdiutil makehybrid -o ../foo -eltorito-boot fdboot.img -iso .
hdiutil burn ../foo.iso
5) Boot up off the disk, Drive X:\ is probably the CD drive (rather than A: which is the disk image fs...)

*phew*