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Re: Debian GNU/Hurd Base Set "gnu-19990104" available now!

> Also, there seems to be a problem booting from internal LS-120 drives.
> Normal operating systems (Windows...) can boot from internal drives if
> the BIOS can handle it. GRUB hangs when I try to boot from an ordinary
> 3,5" disk inserted into the LS-120. I've tested GRUB 0.4, but not
> further explored this issue. It may be a problem of GRUB, but perhaps it
> is a problem of the chipset or the BIOS. I will give a detailed report
> once I've tested it with the newest version of GRUB.

I wrote about this problem earlier in debian-hurd (2 Dec).

I hacked my copy of GRUB so that it works from my internal LS-120. I'm
copying the relevant paragraphs again, below.

By the way, SYSLINUX boots off my LS-120 without problems: it applies
a different algorithm for deciding whether the device is a floppy or a
hard disc. Boot sectors can be quite amusing, really ...


As I wrote before, the GRUB boot floppy provided with gnu-0.2.tar.gz
doesn't work off my LS120 IDE floppy. Neither does the 0.5 release of
GRUB, which I built from source. However, after many failed
experiments, I managed to modify grub-0.5's boot sector so that it
works with both my ordinary and my IDE floppies. (I include the patch
below, and I will tell Erich about my experiences.)


My GRUB patch:

It's just a hack, not a serious attempt to improve the software, but it
did give a floppy that boots off both my ordinary and my IDE floppy drives.

In grub-0.5/stage1/stage1.S the patch is:

< 	andb	$BIOS_HD_FLAG, %al
< 	/* jz	floppy_probe */
< 	.byte	0x0f, 0x84; REL(floppy_probe)
> 	orb	$BIOS_HD_FLAG, %al
> 	/* jz	floppy_probe */
> 	.byte	0x0f, 0x84; REL(floppy_probe)

If you prefer to patch the binary boot sector, the change is:

< 24 80
> 0c 80

That's at address 0x55 in grub-0.5/bin/stage1; the address is
different, no doubt, in the Hurd's boot floppy, which is based on an
earlier release of GRUB, but the same change might work for that too.


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