How to safely remove rest of GTP?

[Andrey V. Elsukov]

On 31.01.2017 18:43, Rodney W. Grimes wrote:
> ... much deleted ...
>>
>>> It is impossible to have a corrupted GPT and some
>>> other type of partition table in the same time.
>
> I believe that statement is in error.
> dd if=/boot/boot0 of=/dev/ada0
> Would not that lead to this very situation if done
> to a GPT parted disk drive?

No, it will not lead to this situation.
/boot/boot0 is similar to /boot/mbr in the example, and with /dev/ada0 
all will behaves like with /dev/md0.

>> Maybe when only using FreeBSD and gpart, but I'm pretty sure I've seen
>> forum users who have tried some crappy other formatting tool and have
>> overwritten the primary GPT with a valid MBR and left the secondary GPT
>> untouched.  This only becomes obvious when they bring the disk back to a
>> FreeBSD system.
>
> As almost all MBR tools are un aware of GPT so well not do anything to
> destroy the secondary GPT, so this is infact very likely to occur.

Please, give me some working example, when or where you have a problem, 
and not some theoretical, based on previous negative experience or memories.

-- 
WBR, Andrey V. Elsukov