Black screen with blinking cursor (corruption?)

balagemayrag · March 10, 2016, 07:10:07 AM

Hi,

I use PLOP boot manager for dual-booting Windows XP and Windows 7 but sometimes the boot manager just goes nuts.

Symptoms

Black screen with blinking cursor, computer freezes, nothing happens.
Black screen with blinking cursor, but I'm able to bring up the menu pressing ESC. The menu is empty, totally missing all of my boot profiles, the screen looks like it was displaying only odd or even rows, black bars appear. If I manage to navigate to boot manager settings, it shows random characters at values for options that have a text-based value.
The second one happens more often. It occurs after doing a clean shutdown/restart from Windows XP. I suppose that some overwrite or corruption occurs to the boot manager. My partition table looks like this. I keep my boot manager in the MBR and the type of the partition table is legacy/BIOS/MBR (not GPT, no UEFI boot, etc.).

Partition table

Code Select Expand
Partition ### Type Size Offset ------------- ---------------- ------- ------- Partition 1 Primary 32 GB 32 KB Partition 2 Primary 32 GB 32 GB Partition 3 Primary 413 GB 64 GB

First I suspected a boot virus but I scanned the whole system as a slave drive (using Kaspersky's live CD) and there were no hits at all. My second tip is that Windows XP, which resides on the first partition, would write something to the MBR (or somewhere between the MBR and the first partition) or some other area that affects PLOP.

Any idea or suggestion is appreciated.

Elmar · March 10, 2016, 08:08:15 AM

Hello,

Autodesk could make such troubles. Are you using Autodesk?

Best regards
Elmar

balagemayrag · March 10, 2016, 08:17:48 AM

I don't use anything from Autodesk.

By the way, I have an SSD (Samsung 850 Pro 512GB). I read about MBR corruption issues at Crucial SSDs, however it has never been proven that it's the fault of the drive. Also on the contrary, this happened to me once when I used to have an HDD. I just reinstalled PLOP and didn't care too much because it didn't happen more times. Now today it's the third in this week when the MBR gets corrupt and I have to reinstall PLOP every time from a boot disk.

balagemayrag · March 11, 2016, 10:40:52 AM

Elmar, could you please tell me how exactly Autodesk causes MBR corruption and why?

It might help me investigating the problem further and bring us closer to a solution.

Elmar · March 11, 2016, 13:48:52 PM

Autodesk writes some license data to sector 5 or 6 (i can't remember exactly) which is used by the Plop Boot Manager.

balagemayrag · March 11, 2016, 14:17:42 PM

Sounds interesting, thanks. What I'm going to do is to backup the very first sectors of my drive then, compare it when the next failure occurs. May bring me further to know what overwrites it.

balagemayrag · March 12, 2016, 15:50:23 PM

Meanwhile I looked at Sector 5 and 6 but there were only some binary data. But I have found PLOP-related data at Sector 60 and Sector 61.

Content of Sector 60

Code Select


Offset(h)   00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

0000007800  00 01 02 00 07 FE FF FF 40 00 00 00 D1 EA FF 03  .....þÿÿ@...Ñêÿ.
0000007810  00 FE FF FF 07 FE FF FF 18 EB FF 03 0A EB FF 03  .þÿÿ.þÿÿ.ëÿ..ëÿ.
0000007820  00 FE FF FF 07 FE FF FF 61 D6 FF 07 4F 3C 9E 33  .þÿÿ.þÿÿaÖÿ.O<ž3
0000007830  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007840  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007850  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007860  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007870  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007880  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007890  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000078A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000078B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000078C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000078D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000078E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000078F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007900  68 64 61 31 00 20 20 20 20 20 20 20 20 20 20 20  hda1.           
0000007910  68 64 61 32 00 20 20 20 20 20 20 20 20 20 20 20  hda2.           
0000007920  68 64 61 33 00 20 20 20 20 20 20 20 20 20 20 20  hda3.           
0000007930  00 64 61 34 00 20 20 20 20 20 20 20 20 20 20 20  .da4.           
0000007940  00 64 62 31 00 20 20 20 20 20 20 20 20 20 20 20  .db1.           
0000007950  00 64 62 32 00 20 20 20 20 20 20 20 20 20 20 20  .db2.           
0000007960  00 64 62 33 00 20 20 20 20 20 20 20 20 20 20 20  .db3.           
0000007970  00 64 62 34 00 20 20 20 20 20 20 20 20 20 20 20  .db4.           
0000007980  00 64 63 31 00 20 20 20 20 20 20 20 20 20 20 20  .dc1.           
0000007990  00 64 63 32 00 20 20 20 20 20 20 20 20 20 20 20  .dc2.           
00000079A0  00 64 63 33 00 20 20 20 20 20 20 20 20 20 20 20  .dc3.           
00000079B0  00 64 63 34 00 20 20 20 20 20 20 20 20 20 20 20  .dc4.           
00000079C0  00 64 64 31 00 20 20 20 20 20 20 20 20 20 20 20  .dd1.           
00000079D0  00 64 64 32 00 20 20 20 20 20 20 20 20 20 20 20  .dd2.           
00000079E0  00 64 64 33 00 20 20 20 20 20 20 20 20 20 20 20  .dd3.           
00000079F0  00 64 64 34 00 20 20 20 20 20 20 20 20 20 20 20  .dd4.

Content of Sector 61

Code Select


Offset(h)   00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

0000007A00  57 69 6E 20 58 50 20 28 33 32 2D 62 69 74 29 00  Win XP (32-bit).
0000007A10  57 69 6E 20 37 20 28 36 34 2D 62 69 74 29 20 20  Win 7 (64-bit)  
0000007A20  00 73 20 68 61 72 64 64 69 73 6B 20 33 00 20 20  .s harddisk 3.  
0000007A30  00 73 20 68 61 72 64 64 69 73 6B 20 34 00 20 20  .s harddisk 4.  
0000007A40  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007A50  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007A60  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007A70  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007A80  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007A90  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007AA0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007AB0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007AC0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007AD0  00 01 01 00 0C 0F FF FF 3F 00 00 00 51 37 77 00  ......ÿÿ?...Q7w.
0000007AE0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007AF0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B00  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B10  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B20  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B30  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B40  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B50  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B60  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B70  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B80  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007B90  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007BA0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007BB0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007BC0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007BD0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007BE0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0000007BF0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................

This must be my partition list and my boot profiles.

There are some binary data at sectors following these (62 and 63) but I can't really figure out where it belongs to. They follow almost the same pattern as Sector 5 and 6, however it's hard to compare them since they're binary and I don't exactly know how PLOP stores its information. The first sector of my filesystem is Sector 64, so it's really close to the PLOP-related data. Is it possible that PLOP tries to use sectors overlapping the filesystem on my first partition? What sectors are used other than 5, 6 (and 60 and 61)?

Elmar · March 12, 2016, 16:18:51 PM

The Plop Boot Manager is using the sector 1 and the sectors from 3 to 63. The sectors 60 to 63 are used for data. The boot manager will not write to to a sector higher then 63.

balagemayrag · March 13, 2016, 09:44:53 AM

Thanks.

Today I experienced the problem again. Then I managed to save the first 63 sectors from my disk. Reinstalled PLOP and did it again. So now I have two images, a working and a non-working one. I compared them. There were only minor differences at Sector 59 and 61 (at each sector only one byte differs).

What's more suspicious is that Sector 32 gets completely overwritten/replaced.

I Googled it and found some software called FlexNet that uses Sector 32 but I definitely do not have this on my system.

Any ideas?

Elmar · March 13, 2016, 09:54:02 AM

The overwriting of sector 32 is definitely the reason why the boot manager stops working.

balagemayrag · March 13, 2016, 10:03:13 AM

I think I found it. It's Adobe Photoshop that writes some computer-specific licensing information/signature to Sector 32. Now I experimented with it. Each time I start Photoshop, PLOP fails to start.

My question is that can I somehow relocate PLOP to a different sector group?

I would resize my first partition, make it start from Sector 2048, then place PLOP above Sector 64. There are too much tools out there that arbitrarily write to these first sectors (Autodesk, Flexnet, Adobe).

Elmar · March 13, 2016, 10:18:36 AM

At the moment, there is no way to install to sector 64.

balagemayrag · March 13, 2016, 11:18:53 AM

Isn't it possible to install plop to a dedicated partition?

Are there other installation options that don't require a separate boot disk?

Elmar · March 13, 2016, 11:58:48 AM

You can use it as secondary boot manager. Then it is stored on a partition and will be started by another boot manager. There are some features disabled in this mode.

balagemayrag · March 13, 2016, 15:32:03 PM

Do you have some HowTo's about this?

It would be fine to put PLOP to a partition and install an MBR with the only purpose and capability to load PLOP.

How do I install PLOP to a partition and what would you recommend into MBR?

balagemayrag · May 06, 2016, 12:23:07 PM

I still couldn't find a good solution.

I would like to create a boot partition and install PLOP there. Could you please recommend me a boot manager that is as simple/small as starts PLOP on the first partition (and doesn't have any pre-loading overhead)?

Also, how can I install PLOP onto a partition? Found no references in the documentation.