Syslinux - Mar 2017 - "isolinux.bin missing or corrupt" when booting USB flash drive in old PC

David Christensen wrote:
> It looks like the call to "error" (line 276) is made if a
summation of
> the bytes in the first four sectors of a partition don't add up to
> HYBRID_MAGIC (?).
HYBRID_MAGIC		= 0x7078c0fb
isolinux_hybrid_signature = 0x7c00+64
...
 cmpl	$HYBRID_MAGIC,(isolinux_hybrid_signature)
 jne	bad_signature
...
bad_signature:
 call	error
 .ascii	"isolinux.bin missing or corrupt.\r\n"
		

No. It looks for the value HYBRID_MAGIC at position
isolinux_hybrid_signature in memory.


-- 
MartinS

On 03/18/2017 10:55 PM, Martin Str|mberg via Syslinux
wrote:
> David Christensen wrote:
>> It looks like the call to "error" (line 276) is made if a
summation of
>> the bytes in the first four sectors of a partition don't add up to
>> HYBRID_MAGIC (?).
>
> HYBRID_MAGIC		= 0x7078c0fb
> isolinux_hybrid_signature = 0x7c00+64
> ...
>  cmpl	$HYBRID_MAGIC,(isolinux_hybrid_signature)
>  jne	bad_signature
> ...
> bad_signature:
>  call	error
>  .ascii	"isolinux.bin missing or corrupt.\r\n"
> 		
>
> No. It looks for the value HYBRID_MAGIC at position
> isolinux_hybrid_signature in memory.
Okay.


What syntax is used in isohdpfx.S -- it doesn't match my Intel 
8086/8088/8087/80186/80188 Programmer's Pocket Reference Guide from 1982?

http://git.zytor.com/syslinux/syslinux.git/tree/mbr/isohdpfx.S


David