[issue1560] Unable to modify partition table on ThinkPad T61p during install

[Jens Rehsack]

Thomas Nikolajsen (via DragonFly issue tracker) wrote:
> Thomas Nikolajsen <thomas.nikolajsen at mail.dk> added the comment:
> 
> It seems like you don't have a recognized MBR on 'ad0'.

Believe me: I have - dozen times. Rebooting between assuming the kernel
caches the current (empty) MBR, powering off the machine - and as I told,
using as well Linux and Windows XP to create a partition including a
filesystem on the disk: DragonFly see always the attached MBR - regardless
what I've done before.

> Installing an initial MBR can be done by:
>   fdisk -BI ad0

Tried - because it's described in /README

> Updating the MBR can be done by:
>   fdisk -u ad0

As in FreeBSD since ages (I'm FreeBSD user since 2000 or so ...)

> If you would like to have multiple OSs installed,
> a boot manager can be installed in MBR by:
>   disklabel -B ad0
> 
> How did you try to modify MBR; using installer or manually?

Both.

> If manually; which commands did you use?
> (e.g.
>   dd if=/dev/zero of=/dev/ad0 bs=512 count=32

I used "dd if=/dev/zero of=/dev/ad0 bs=32k count=16 (later I tried count=640)

>   fdisk -BI ad0
>   dd if=/dev/zero of=/dev/ad0s1 bs=512 count=32
>   disklabel -w -B ad0s1 auto
>   disklabel -e ad0s1
> as example in disklabel man page)
> 
> Are you sure the HD you would like to modify is 'ad0'?
> 'da0' is first AHCI / SCSI attached disk,

da0 is the "internal" windows disk (seen by both NTFS partitions on it).

> 'da8' is first external disk (e.g. USB attached),

USB stick I used to copy the logs.

> 'ad0' is first ATA / SATA, non-AHCI attached disk.

The empty disk I want to use to put DragonFly BSD on it.

> Your logs show several disks, ad0, ad8 & da0, in system:

I couldn't see anything in the dmesg log, but I thought a developer might do ...

Jens