Author Topic: Multiboot - install with cleared partition  (Read 4987 times)

malko

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Multiboot - install with cleared partition
« on: December 12, 2016, 17:52:23 PM »
Hello all,

I don't know if this topic has already been answered (cannot find). Thanks to redirect me if so.

Here is  the situation:
- PC with 2 partitions (windows)

- 1st partition from sector 0 to 245118975 (ntfs)
- plop boot manager installed (mbr + boot menu)

- 2nd partition from sector 245118976 (ntfs)

- each partition clear the other when booting (p1 cannot see p2 and vice versa)

- problem with os on second partition
- gparted to format 2nd partition
- usb key to reinstall the os on second partition

- and of course I forgot that windows will write a new MBR on install... :(

- reinstalled plop from 2nd partition (mbr + menu)

The problem:
I cannot access the 1st partition any-more !
Is there a way to find the value that should be manually written to the partition part of the plop boot manager to be able to access the 1st partition again ???

Please HELP  and thanks in advance !


Elmar

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Re: Multiboot - install with cleared partition
« Reply #1 on: December 13, 2016, 06:29:19 AM »
Hello,

- and of course I forgot that windows will write a new MBR on install... :(

- reinstalled plop from 2nd partition (mbr + menu)

Option 2 of the install program should have been the right choice. That keeps the boot manager data.


I cannot access the 1st partition any-more !
Is there a way to find the value that should be manually written to the partition part of the plop boot manager to be able to access the 1st partition again ???

You can try the program Testdisk to recover the entry for the lost partition. In the worst case, its possible to calculate the values by hand.

Best regards
Elmar

malko

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Re: Multiboot - install with cleared partition
« Reply #2 on: December 13, 2016, 14:09:22 PM »
Hello Elmar,

Thank you for your reply.

Option 2 of the install program should have been the right choice. That keeps the boot manager data.

In fact this what I did (rewrite the loader). But at the end, I had no possibility to boot on the 1st partition and only the 2nd one with the new installed os was available within plop.

You can try the program Testdisk to recover the entry for the lost partition. In the worst case, its possible to calculate the values by hand.

I have downloaded Testdisk and followed the guide to recover the 1st partition. Unfortunately, even if Testdisk told me that the 'write' was successful, it didn't changed anything for plop. Still no 1st partition. ??

I retried it once - 2nd attempt (still no 1st partition within plop) and again - 3rd attempt (and again no 1st partition within plop).   >:(

What I don't understand here, is that usually when there is a partition change, plop display a big warning in red asking for a confirmation.
But after using Testdisk and writing the Table to the disk, there was no warning from plop. Do you have any idea about this behaviour ?


I then had the idea to change the "cleared" to "don't touch" in plop and rebooted twice (experience showed me that it need reboot for plop to display values for previously "cleared" partition in 'edit mbr/import data'). I don't know if this is normal but it is what I have seen.

I then retried Testdisk.

But no 1st partition within plop...   :'(

I then by hazard tried option 2 (rewrite the loader).

This time plop displayed me values in 'edit mbr/import data' :o . Houra !  ;D
So I wrote the values down :) set the PB line correctly and re-set to "cleared" in place of "don't touch".

Actually PC seems ok. Both partitions boot and diskmgmt.msc display free space instead of other os.

Thank you for your help Elmar and thank you to the guy who coded Testdisk :)