[syslinux] Syslinux: Broken file reading for fat16 with 3.35+?

[H. Peter Anvin]

Ram Yalamanchili wrote:
> 
> Anyone know what might be causing this? Looks like ldlinux.sys is
> broken. I need to upgrade to 3.35 because I need the 0x19 read
> partition call for my use. On a similar note, Peter, are you ok with
> me implementing a comboot api call which would take in the bios drive
> and sector number to get data from (a 0x20 if you will)? Or 0x19 can
> be modified to take in an argument which says if the partition offset
> shoudl be added to eax or not before you issue the int 0x13h. I like a
> newer call which is a "Read raw disk" instead of "read active
> partition". I want to extend it to read from (drive number, partition
> number). 
> 

There is no useful reason to make an API call for that -- syslinux 
doesn't use that directly.  If you're looking for the active partition 
offset, you can find it through int 0x22 AX=0x000a as [es:bx+8].

To handle multiple partitions, you need to know how to walk the 
partition tree.  chain.c32 has that code in it, it would make more sense 
to turn that code into a library.

 > Further extension could lead to Grub like addressing where
 > you can have files on various other partitions and be able to get
 > them.

No way in hell, sorry.  I consider that the pinnacle of bad design, 
since it means the boot filesystem isn't self-contained.

	-hpa