I have the boot block disassembled and commented, I worked on this issue
I think it's too early in the boot process to be the same xenix bug that
affects Xprofile and needs a patch.
I'll ask my son to explore my other laptop at home to find the code (I did
not put those files on the public cvs repository).
> James MacPhail <g...@sigmasevensystems.com> Sep 02 08:53AM -0700
> >did anybody manage to boot Xenix directly from hard disk
> Yes, I was able to get Xenix 3.0 to boot from a ProFile/emulator or
> Widget connected to the built-in port. (However, Xenix 2.3, the
> version distributed on Twiggy disks, does not install boot code on
> the hard disk)
> >What qualifies a working boot block? The "AAAA" signature is present.
> For Lisa to attempt to boot a device, all it requires is 0xAAAA at
> offset 4 in the tags of block 0. If that signature is present, Lisa
> will execute the code in block 0. No other checks are performed.
> >Does the boot code start at offset 0x14 (after the tag bytes)?
> Yes, the code does start at offset 0x14, the first byte in the data
> field after the tags. (For a Widget, the code starts at offset 0x14
> in the data field, as the boot ROM loads block 0 from a Widget using
> the ProFile code.)
> >when I try to boot from HD Lisa throws a "75" error (bad system
> >file). It never tries to access any other block than 0000, so
> >something seems to be wrong with that boot code.
> When an error occurs while loading block 0, the error code is
> generated by the boot ROM. However, I believe we commonly see errors
> 80-85 when attempting to load a boot sector from a ProFile, so it may
> be the Xenix code that is returning error 75.
> If the boot code in block 0 returns to the boot ROM, it can pass any
> error code, so error 75 could mean anything to Xenix.
> My guess is that Xenix thinks there is a ProFile handshaking problem.
> Consider applying the patches from
> http://SigmaSevenSystems.com/xpf_xenix.html and re-installing the
> patched Xenix on the hard drive (or perhaps you can apply the patches
> directly to the hard drive partition if using an IDEfile).
> Let me know if the problem persists and I will disassemble the boot
> block code to see if there are any clues as to what error 75 means.
> I think you can boot with a trick. something like breaking normal
> procedure and forcing profile boot. if you boot with default device
> register is 0 and xenix boot code fails. If you force a real boot
> register has another value.
> It's a bug between boot eprom and xenix boot code.
> I have more information about this bug on my other laptop where I
> coded Idle... problem is I'm 9500km from home :)
> 2012/9/2 <firstname.lastname@example.org>
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