12 replies to this topic

[awowy]

Hi my problem is similar to this post "Strange Problem? Can't find GRLDR!, MBR Can't find GRLDR"

Basically when trying to create a boot flash drive, somehow Grub4dos was installed on the Hardrive instead, so now whenever I start my PC, a boot screen appears saying "Cannot find grldr in all devices" before that after the first boot i got this:

try (hd0,0): NTFS5: No grldr

try (hd0,1): invalid or null

try (hd0,2): invalid or null

try (hd0,3): invalid or null

try (hd1,0): Fat16: No GRLDR

try (hd1,1): invalid or null

try (hd1,2): invalid or null

try (hd1,3): invalid or null

Error: Cannot find GRLDR in all devices. Press ctrl + alt + del to restart.

Some one told gfreed (the guy from the post I mentioned) to copy the grld file to his hardrive, but i do not know how to do this unless is using windows XP, which I cannot access.

After this issue gets solved, I would like to know how to make the Hardrive to start normally instead of using grub4dos bootscreen, as I only intended to use it on my flashdrive, NOT the hardrive. I mean to uninstall grub4dos from my Hardrive.

I couldn´t understand how he did it, as this is the first time I use grub4dos, I only wanted to make a Hirens boot flash drive to repair another PC, and now I have 2 nonfuncioning PC s lol

EDIT: i managed to copy the grldr file into the hardrive by slaving it into another PC. now im able to run windows xp, but as I said before, I would like to know how to eliminate that boot window that Grub4dos created, meaning, I just want to uninstall it so that i can login to windows normally as if this never happend lol, hope someone knows how pleaaaaase

[wimb]

Grub4Dos Installer 1.1 has option to Restore from PrevMBR.
It will use then the Backup MBR written on Sector 1 of your Harddisk (Sector 0 is first sector with MBR)

This is the most easiest way to Undo the effect of Install of Grub4Dos in the MBR on the wrong disk.

You can use this option if you previously had (wrongly) used Grub4Dos Installer 1.1

In that case after booting with Windows:

• Run Grub4Dos Installer 1.1
• Select as Disk your Harddisk (recognise it also by its size)
• Check option to Restore from PrevMBR
• Use Install

After Reboot, everything should be normal again.


Before everything, you may want to study Sector 0 and sector 1 of your Harddisk, by using TinyHexer (also part of U_XP_SET package). It will give you more insight in what you are going to do. Use Disk > Open drive ... > PHYSICALDRIVE0

And I advice before working on MBR, always to Run first MBR_Backup.cmd so that you have Backup Files of MBR , 1st Head (= 63 Sectors) and BootSector.
MBR_Backup.cmd is also part of U_XP_SET package.

More Info on U_XP_SET package:
http://www.boot-land...?showtopic=5306

[was_jaclaz]

The above IF the original MBR was actually saved to Sector 2 (which is not something we know right now).

@Wimb
Sector 1 is first sector on Hard Disk, it is at offset 0.
Second sector is sector 2, it is at offset 1.

It is safer to re-write just the MBR CODE to sector 1.

A handy utility is MBRFIX:
http://www.sysint.no...ting/mbrfix.htm

MbrFix /drive <num> fixmbr {/vista} Update MBR code to W2K/XP/2003 or Vista

http://www.sysint.no...US/Default.aspx


jaclaz

[wimb]

It is safer to re-write just the MBR CODE to sector 1.

MBRFix.exe is certainly very useful,
but not always safer.

There are cases e.g. Acer Laptop with manufacturer specific MBR BootCode, which you could not restore with MBRFix.exe

Using Grub4Dos Installer 1.1 with option Restore from PrevMBR is also safe when there is no MBR Backup made on the second sector (Sector 1 in TinyHexer).
It will recognise this and do nothing.
Also Restore from PrevMBR will not change the partition table, it will only restore MBR Bootcode.

@jaclaz
TinyHexer follows LBA numbering of Sectors starting with Sector 0,
whereas you follow C/H/S numbering starting with Sector 1
But we are speaking of the same sectors:
first sector is MBR
second sector is Backup of PrevMBR

[was_jaclaz]

@wimb

Yep.

But the info about LBA "numbering sectors starting from 0" (which is everywhere on the internet), though seemingly accurate (and actually "working" ) is a little tiny teeny bit misleading.

A LBA "StartSector" value is actually an offset "from" something.

A LBA "NumSectors" is a number of sectors.

To be more accurate a C/H/S value like 0/1/1 actually means "Sector #1 on Head #1 on Cylinder #0" (with sectors numbered from 1, Heads and Cylinders numbered from 0).

The corresponding LBA StartSector=63 does not actually mean "the sector #63 with sectors numbered from 0", but rather "the sector which is at offset 63 from the beginning of the disk" or, if you prefer, "the sector that has 63 sectors before".

The idea that sectors are "numbered" in LBA notation is just, as I see it and AFAIK, a simpler way to describe the logic behind LBA way of addressing, but not fully accurate.

MBRFix.exe is certainly very useful,
but not always safer.

There are cases e.g. Acer Laptop with manufacturer specific MBR BootCode, which you could not restore with MBRFix.exe

Sure , as well as any "stupid" laptop, like the HP ones, and GOD only knows how many, that have "misterious" Recovery Partitions.

Using Grub4Dos Installer 1.1 with option Restore from PrevMBR is also safe when there is no MBR Backup made on the second sector (Sector 1 in TinyHexer).
It will recognise this and do nothing.

Didn't know that there was this kind of "safety".
Thanks for the info.

Also Restore from PrevMBR will not change the partition table, it will only restore MBR Bootcode.

Hmm , another thing I didn't know, not using grubinst at all.

But is the actual MBR DATA copied to second sector?

I mean, if for any reason the MBR DATA (in the "real" MBR) gets corrupted, can second sector be used to restore the DATA?



jaclaz

[wimb]

But is the actual MBR DATA copied to second sector?

Yes, the complete first sector (MBR + partition table) is copied as Backup by grubinst.exe to the second sector. So restore of the partition table is possible as well, but grubinst.exe will restore only the MBR boot code.

Thus using Restore from PrevMBR option of grubinst.exe is very safe to restore the MBR bootcode.

[online]

@wimb
@jaclaz

How about fixmbr from RC and a (presumable) "global" safety, in your opinions?

[was_jaclaz]

@wimb
@jaclaz

How about fixmbr from RC and a (presumable) "global" safety, in your opinions?

It does EXACTLY the same thing MBRFIX does.

Actually MBRFIX was originally written to have the - at the time missing - EXACT same functionalities (and a few more added ) of the RC fixmbr.

Basically the idea is the same, replace the MBR CODE leaving intact the MBR DATA.

Of course if the previous MBR CODE was not the "standard" one, it is overwritten and lost forever.

On the other hand, restoring a saved MBR (and here comes the news for me - of the behaviour of grubinst.exe) while may restore the "standard" or "non standard" MBR CODE, could, if the backup was made incorrectly for any reason or with a changed partitioning scheme or after something already corrupted the original MBR DATA, overwrite the DATA, which will then be lost forever. (but still fully recoverable by using TESTDISK ).

In other words, if anyone is 100% positive that the backup MBR contains BOTH correct CODE and DATA, the esiest and safest is to restore it integrally.

If there are doubts about the correctness of EITHER the CODE or DATA, separate approaches might guarantee an increased safety.

This batch can do the trick (you need dsfo and dsfi in same directory you run the batch into) :

@ECHO OFF:: MBR_PLAY.CMD: small batch to play with MBR CODE and DATA (or BOTH) by jaclaz:: Just a basic example, Release 0.01 14/06/2009:: A copy of a MBR is needed to start playing ;-):: Usage::: 	MBR_PLAY.CMD <drivenum> </option> <MBR_to_be_restored>:: Where::: 	<drivenum> is a Physical drive number, first drive is Physicaldrive0:: 	</option> is EITHER of: /CODE /DATA /BOTH:: 	<MBR to be restored> is the filename of the MBR to be restored:: ALL parameters are compulsory.IF %1.==. GOTO :HelpIF NOT %1.==. SET Drivenum=%1FOR %%? IN (0 1 2 3 4 5 6 7 8 9) DO IF %drivenum%.==%%?. GOTO :DriveOKCALL :Error IF %drivenum%.==%%?.&GOTO :EOF:DriveOKIF NOT %2.==. SET Param=%2IF /I %param%.==/CODE. GOTO :ParamOKIF /I %param%.==/DATA. GOTO :ParamOKIF /I %param%.==/BOTH. GOTO :ParamOKCALL :Error IF /I %param%.==&GOTO :EOF:ParamOKSET previous_mbr="%3"IF NOT EXIST %previous_mbr% CALL :Error IF NOT EXIST %previous_mbr%&GOTO :EOFIF EXIST now.mbr CALL :Error IF EXIST now.mbr&GOTO :EOFIF EXIST now_head.mbr CALL :Error IF EXIST now_head.mbr&GOTO :EOFIF EXIST now_data.mbr CALL :Error IF EXIST now_data.mbr&GOTO :EOFIF EXIST now_tail.mbr CALL :Error IF EXIST now_tail.mbr&GOTO :EOFdsfo \\.\PhysicalDrive%DriveNum% 0 512 now.mbrdsfo now.mbr 0 446 now_head.mbrdsfo now.mbr 446 64 now_data.mbrdsfo now.mbr 510 2 now_tail.mbrIF EXIST before.mbr CALL :Error IF EXIST before.mbr&GOTO :EOFcopy /b "%3" before.mbrIF /I %param%.==/BOTH. copy /b  before.mbr to_write.mbr&GOTO :Write_MBRIF EXIST before_head.mbr CALL :Error IF EXIST before_head.mbr&GOTO :EOFIF EXIST before_data.mbr CALL :Error IF EXIST before_data.mbr&GOTO :EOFIF EXIST before_tail.mbr CALL :Error IF EXIST before_tail.mbr&GOTO :EOFdsfo before.mbr 0 446 before_head.mbrdsfo before.mbr 446 64 before_data.mbrdsfo before.mbr 510 2 before_tail.mbrIF /I %param%.==/CODE. copy /b before_head.mbr + now_data.mbr + before_tail.mbr to_write.mbr&GOTO :Write_MBRIF /I %param%.==/DATA. copy /b now_head.mbr + before_data.mbr + now_tail.mbr to_write.mbr&GOTO :Write_MBRGOTO :EOF:Write_MBRECHO Following command is:ECHO dsfi \\.\PhysicalDrive%DriveNum% 0 512 to_write.mbr::******************************************************REM UNREM FOLLOWING LINEREM dsfi \\.\PhysicalDrive%DriveNum% 0 512 to_write.mbrREM UNREM ABOVE LINE::******************************************************ECHO.SET Clean_the_mess=SET /P Clean_the_mess=DO YOU WANT TO CLEAN TEMPORARY FILES? (Y/N)IF /I %Clean_the_mess%.==Y. CALL :Clean_the_messGOTO :EOF:ErrorECHO oh, oh! Something went wrong somewhere.....ECHO Last command was: %*PAUSEGOTO :EOF:HelpFOR /F "tokens=1,* delims= " %%A in (%~dpnx0) DO IF %%A==:: ECHO %%BGOTO :EOF:Clean_the_messFOR %%? IN (beforebefore_headbefore_databefore_tailnownow_headnow_datanow_tail) DO IF EXIST %%?.mbr del %%?.mbrGOTO :EOF

It WON'T actually write ANYTHING to a Physicaldrive unless you UNREM the actual writing line.



jaclaz

[online]

@jaclaz

So many thank for your exhaustive reply.

Btw: many thanks to wimb too (for his new report and new related knowledge).

[awowy]

OMG, thank you guys sooo much for your comments,

I lost track of the topic and finally found it, I didnt get any email notifications about the comments

I will read everything carefully and hope something solves the issue, for what I read-scanned it was at least helpfull to someone.

so, I will post and update and let you guys know how it went, crossing my fingers

[awowy]

**SOLVED**

k, So I did what you guys told me:

1) I tried Restoring from PrevMBR using Grub4dos but as it turns out I did not made a backup, so that did not worked.

2) I then used MBRFIX, when I opened the exe file a DOS command window appeared, but closed inmediatelly, so I could not even enter the commands you told me to, tried several times, the same thing kept on happening, even in safe mode, so that didnt worked either.

3) I decided to make a repair installation of Windows Xp from the boot CD, it did repair Windows but did not changed the MBR.

4) Finally I decided to use the Windows Repair Console, and used the FixMBR command, THAT DID WORKED for me and now I dont get that boot screen that asked me to choose what to boot from which was very annoying.

So, thank you guys so much for your time and help.... As of now I will backup everything that I decide to experiment with, and read as much as possible before hand, this would not have happened if I had done so that way.

PS: Sorry I didnt replied ebfore, I was away on vacation

[was_jaclaz]

2) I then used MBRFIX, when I opened the exe file a DOS command window appeared, but closed inmediatelly, so I could not even enter the commands you told me to, tried several times, the same thing kept on happening, even in safe mode, so that didnt worked either.

Sure , MBRFIX is a command line app.

You need to open a command prompt and execute MBRFIX in it.

Altrernatively, you can use my little pseudo-GUI for it:
http://home.graffiti....net/index.html
but you will need also the Wizard Apprentice.

Or any of these other GUI's:
http://www.911cd.net...showtopic=16470
(this one needs to be "re-connected", I'll Ask Nuno to restore http://red.boot-land.net/index.html )

Also this one:
http://www.911cd.net...o...c=10956&hl=
whcih seems like "desaparecida".

It can be however found inside the BartPE plugin on anwald's site:
http://www.anwald.com/
http://www.anwald.com/coolXPE/umbr.rar

jaclaz

[awowy]

lol, didnt know that, no wonder it closed inmediatelly everytime.

Hope that info is usefull for someone else viewing this topic.


Thanks again