OK, results:
# gdisk /dev/sda
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
I believe that's what I need. Windows 8.1 OS is still there but won't
boot which I expected. So I'm going to need to reinstall 'dows 8.1
again, which I expected. However my ding dong computer did not come with
a reinstalll disk. So I hope I can get that from either ASUS (ASUS
X550CA notebook) or the beloved ones at Microsoft. I will be very
surprised if that doesn't cost me some $. Ok take one for the team.
Konstantin this is important because Colin Close and I are trying to
dial in OpenMandriva support for efi/uefi and also multibooting with
Windows. Your help has been invaluable. Any more input will be much
appreciated. We seem to have much in front of us.
Colin: unless and untill I have the wherewithall or whatever to
reinstall Windows 8.1 we're paused. I will work on that as time allows.
The positive side is I'm learning a lot about 'dows and how to
munipilate it and gdisk and other stuff that may lead to
incontrovertible results. And that, to me, is the goal. So I am forced
to learn more about the windows side of these issues as well as learning
the GPT (gdisk is to GPT as fdisk is to MBR) stuff, the UEFI stuff, and
so forth. I have a lot of aforementioned man pages bookmarked for study...
Obviously I'm dealing with a major learning curve. Any one out there
help me if you can. I darn sure need it.
Thanks,
Ben
ben79
-------------------------------------------------------------------------
OM-QA Team
On 10/27/2014 01:21 PM, Konstantin Vlasov wrote:
Re[2]: [OM Cooker] How to partition for dual boot Windows 8.1/OM Lx
2014.1 on UEFI computer. Hi, Ben.
I see. OK then, there is a short (but somewhat risky) way and long
(but reliable) way. The short is just to ignore the damaged GPT by
simply converting MBR into new GPT and hoping it would be all right.
But I'd suggest to go risk-free.
Of course, backup of the partition table is always desirable. So,
before starting, you can use
# dd if=/dev/sda of=/path/to/backup/file bs=512 count=34
for saving the MBR and primary GPT contents into file (backup GPT can
be copied similarly, but its position is a bit difficult to fetch:
it's stored in primary GPT itself in binary form; usually it's located
within the last 33 sectors of the disk, but I'm not sure there is no
aligning or something like that; you can backup the last megabyte or
so of your disk to make sure).
1. After starting `gdisk /dev/sda' tell it to use GPT (variant 2).
2. Now enter recovery menu (r), load main GPT table (e) and print its
contents (p).
3. Then load backup GPT table (c) and print it (p).
4. Compare all the 3 results: both GPT tables and MBR (printed earlier
by parted -l). Now:
5a. If they are all identical, do nothing and go to p.6.
5b. If only one of GPT copies corresponds to the real partitioning
structure, load the valid copy of GPT (c or e, as from pp. 2-3 given
above).
5c. If both GPT copies are wrong, and only MBR is correct, regenerate
GPT from MBR (f).
6. Now save the resulting partition table as GPT (w): it will repair
the CRC, update both GPT copies and write the protective MBR to make
it a valid GPT partitioning.
gdisk reports: Caution: invalid backup GPT header, but valid main
header; regenerating backup header from main header.
Caution! After loading the partitions, the CRC doesn't check out!
Warning! Main and backup partition tables differ! Use the 'c' and 'e'
options on the recovery & transformation menu to examine the two tables.
Warning! One or more CRC's don't match. You should repair the disk!
Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: damaged
Found valid MBR and corrupt GPT. Which do you want to use? (Using the
same GPT MAY permit recovery of GPT data.)
1 - MBR
2 - GPT
3 - Create blank GPT
Your answer:
All this is the result of simply running gdisk>/dev/sda. And for what
it's worth I haven't answered yet.
Thanks,
Ben
ben79
-------------------------------------------------------------------------
OM-QA Team
/--
Bye. With best regards,
Konstantin Vlasov. /
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