[syslinux] USB key: CBIOS line printed, nothing else

[Josh Lehan]

H. Peter Anvin wrote:
> If you don't get a configuration file it defaults to loading a file 
> named "linux", so that's indeed what's happening.

Thanks, that's what I thought.

> Now, the fact that it gets that far (it has loaded the entire 
> ldlinux.sys) and then doesn't get the configuration file is a bit odd. 

So it has finished loading LDLINUX.SYS, that is good.  It means that it 
can see enough of the filesystem to get in this file, which would rule 
out a BIOS geometry issue.

Is there a problem with using the 0x0C filesystem type (FAT32 LBA)? 
That's what I'm using.  Should be the same as 0x0B (FAT32 CHS), since 
the only difference is the flag to Windows to tell it to prefer LBA 
instead of CHS.  I noticed that the "mkdiskimage" script doesn't write a 
partition type of 0x0C by default.  I had to make a quick little patch 
to it, to have it write 0x0C instead of 0x0B.  Might this have killed it?

I'd still be interested in seeing what information the BIOS is passing 
to SYSLINUX.  It might be worth adding some debugging information to the 
"safe, slow, and stupid" loader (syslinux -s), like the optional feature 
that is already available for ISOLINUX.

I'd love to figure out what is unique about this BIOS, and what it is 
sending to SYSLINUX, that confuses SYSLINUX and prevents it from finding 
the configuration file.

Like you said, it's weird that it can boot correctly, and find the 
LDLINUX.SYS file correctly, but then fail to find the SYSLINUX.CFG file. 
  It works perfectly on all the other computers I have tried, which is 
strange!  It must have something to do with this BIOS, but I can't 
figure out what.

It'd be useful to see what the geometry is that the BIOS is reporting 
(the FDPT or EDPT), and also, the extra LBA information available from 
the INT 13 extensions.  I'd put this in myself, but I'm incredibly rusty 
with 80x86 assembler.

> One thing that might be worth watching for is to make sure VFAT hasn't 
> mangled any of your filenames (mount your disk with "-t msdos" to verify 

Thanks for the tip.  I just checked and all the files used during bootup 
are clean (no "squiggle-1").

> that).  Another option would be to try "syslinux -s", or try using 

Thanks.  I tried just "syslinux" before, and am using "syslinux -s" now. 
  It did not make a difference.

> EXTLINUX (on ext2fs).

I'd prefer not to use EXTLINUX if possible, because it's also handy to 
have my USB key easily accessible from Windows.  I did prototype an 
early version of KNOPPIX over EXTLINUX here, though, and had success 
with it:

http://www.knoppix.net/forum/viewtopic.php?t=23431

> As for CBIOS versus EBIOS; SYSLINUX will use EBIOS if it's available, 
> since EBIOS doesn't have the cylinder 1024 limitation.

Interesting.  I'm still wondering why CBIOS is used.  This is a fairly 
new PC motherboard (Athlon 64 3200+).  The hard drive in there is 80GB, 
and is fully seen and works perfectly from the BIOS, so the INT 13 
extensions should be well in place by now.  Maybe the BIOS manufacturer 
(Award) just really cheaped out on USB booting.  At any rate, my USB key 
only has 977 "cylinders" on it, so it shouldn't make a difference.

Josh