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Grub4dos problem with Syslinux 4

Posted: Sun Sep 19, 2010 8:25 pm
by Victor Chew
Looks like grub4dos "chainloader" command is broken on syslinux 4. Trying to execute:

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chainloader /boot/isolinux/isolinux.bin || chainloader +1
gives:

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Error 13: Invalid or unsupported executable format
Any workaround for this?

Re: Grub4dos problem with Syslinux 4

Posted: Mon Sep 20, 2010 10:56 am
by Icecube
grub4dos uses some magic bytes to determine if the chainloaded file is isolinux.bin or not.
This magic bytes are not the same between all releases. I will ask the grub4dos developers to support the newer version too.

Re: Grub4dos problem with Syslinux 4

Posted: Wed Sep 22, 2010 12:15 pm
by Icecube

Re: Grub4dos problem with Syslinux 4

Posted: Sat Sep 25, 2010 3:07 pm
by Victor Chew
Thanks! Will try.

Re: Grub4dos problem with Syslinux 4

Posted: Tue Dec 21, 2010 1:42 pm
by kcarney
I believe this is broken for USB switching from grub4dos menu to syslinux
Cannot chainload ISOLINUX from a non-CDROM device.
Partition table not recognized(boot_drive=0x80, err=1)

Error 43: The BPB hidden_sectors should not be zero for a hard disk boot sector


Re: Grub4dos problem with Syslinux 4

Posted: Tue Dec 21, 2010 2:16 pm
by Icecube
Did you had problems with the same USB stick before?
Did you reformat/repartitioned it in the meanwhile?

I think, I had the same issue (Error 43: The BPB hidden_sectors should not be zero for a hard disk boot sector) in the past.
Syslinux doesn't care about that field, but grub4dos complains about it. I patched the byte manually. I think your partition will probably be a logical partition.

I think I confirmed the "problem" with running boot_info_script. You can do that from Parted Magic.

Re: Grub4dos problem with Syslinux 4

Posted: Tue Dec 21, 2010 2:22 pm
by kcarney
I think you may be right, something seems weird in the way it is formatted. There are 0 hidden sectors when I believe there should be 63. I'll give the script a try and see what it says.

Any way to bypass the complaint grub4dos has? In a few hours I haven't found any on my own.