[syslinux] Re: Trying to figure out why my Cruzer Micro 512"MB" won't boot.

Josh Lehan jlehan at scyld.com
Tue May 2 19:54:13 PDT 2006

Nazo wrote:
> have, and I can't be 100% sure, but, the BIOS did act like it was a
> harddrive -- in fact, it didn't say "USB Harddrive" or anything like
> that, but, actually showed "Cruzer Micro" in the list of harddrives to
> boot.)  I'm 99% sure that it did boot as USB-HDD despite the

My BIOS is like that (whatever's on the ASUS A8N-SLI motherboard, I'm 
guessing it's Award).

> that it should though.  I mean, a ZIP disk does follow the basic
> standards for a harddrive, it just adds that one little signature
> peice of weirdness with the only partition being the last primary for
> some reason (makes me wonder if they intended for you to be able to
> place another primary partition or something for hidden data or
> perhaps for extra diagnostic utilities or something.  I have a grand
> total of 0 zip disks or drives available to actually test such a
> theory on.)

There's a second little signature weirdness: the geometry, */64/32.

As for using the 4th partition, I believe Iomega used the last partition 
instead of the first, simply out of sheer ignorance.  As for Iomega's 
quality control: http://grc.com/tip/codfaq1.htm

Everything I could find would seem to indicate there should be no real 
difference among the 4 partitions in the MBR, as long as only one of 
them is marked active.  Back when I had working ZIP disks, the 4th 
partition completely spanned the disk, and there were no extra hidden 
partitions or anything like that.

I'd be interested in hearing the real story behind this strange use of 
the 4th partition, if there is one.

> anyone else have a BIOS which supports booting USB-HDD and a
> little time?  If so, could you be kind enough to test your flashdrive
> with the mkdiskimage fake ZIP drive trick and see if the BIOS will
> sucessfully boot in USB-HDD mode?  IMO, if they all work like this,

On my BIOS, it only supports USB-HDD (to my knowledge).

I zeroed a USB thumbdrive and installed a new MBR from scratch, changing 
it manually to the 2 things I know about the USB-ZIP format (use of the 
*/64/32 geometry, and use of the 4th partition).

It formatted and installed OK.

It also booted OK.  I could notice no difference at all.

This would make sense, if what I think is true: the only difference 
between USB-ZIP and USB-HDD, is that USB-ZIP imposes the extra 2 
requirements above.  USB-HDD-compliant drives would then just be a 
superset of USB-ZIP-compliant drives.  Does anybody know for sure?

> there is no reason not to just go straight to USB-ZIP for maximum
> compatibilitie (after all, you never know when you may need to use it
> on a system which does not support USB-HDD, such as maybe a friend's
> computer or something.)

I'd recommend this as well.


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