[syslinux] "isolinux.bin missing or corrupt" when booting USB flash drive in old PC

[Thomas Schmitt]

Hi,

MartinS wrote:
> > > Then you'd want the x86 manuals from amd or intel for the instructions
> > > themselves but they are documented backwards.

i wrote:
> > What do you mean by this statement ?

> Haven't you read the manual yet?...
> "info gas machine i386 i386-syn i386-var".

I still don't get the "backwards" aspect. (Probably not enough background
knowledge.)


> > If the first ".byte 0x33, 0xed" before the "nop"s gets removed then the
> > second one after the "nop"s needs to be removed, too.

> Why? There's no reason from coding perpesctive. That's an xor bp, bp.

You are right. My own program lets the second instance survive and
only overwrites the first one.
I thought it would have side effects which would be reverted by the
second command.

These bytes shall do nothing in case that no Apple Partition Map gets
announced. With isohybrid option --mac or xorrisofs -isohybrid-apm-hfsplus,
the first 32 bytes get replaced by a pseudo APM header:

  45  52  08  00  00  00  90  90  00  00  00  00  00  00  00  00
  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00

which interpreted as x86 code shall still do nothing.


Have a nice day :)

Thomas