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congnt92

Need Help! Modify bootmgr windows 8

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Hi all

I want to modify bootmgr windows 8 where value bcd change to bc1, bc2... How can I do it?

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You will need bmzip and PEChecksum by Jeffrey Bush

First decompress bootmgr

bmzip bootmgr bootmgr.exe

Joakim has found out how to Modify bootmgr of Windows 8

Here you have the adresses for bootmgr.exe version 6.2.9200.16384 (RTM)

So use a HexEditor and change following bytes in bootmgr.exe.

0000066B: 0F 90
0000066C: 88 90
0000066D: A3 90
0000066E: 02 90
0000066F: 00 90
00000670: 00 90

0002957A: 74 EB

000295A1: 75 EB

At adress 8345C you have the \Boot\BCD string that you can change.

Then use PEChecksum to update the Exe checksum

PEChecksum bootmgr.exe

And Finally recompress bootmgr

bmzip /c bootmgr.exe bootmgr

bootmgr-tools.zip

Edited by JFX
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thanks JFX. I hex edit successed. God bless you :angel :angel :angel But after modified bootmgr, when I boot setup windows 8, prompt stopped about 5 seconds. Then the installation can be continue. How do I fix it ?

Capture-3.png

Edited by congnt92
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Are you sure that delay comes from bootmgr?

It boots instantly for me!

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I'm sure. Because if I use bootmgr original, no matter what happend. You can send me your bootmgr file after modified?

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Might be better to post yours so we can see what you did wrong, and suggest ways so you can do it correctly next time.

Cheers and Regards

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Might be better to post yours so we can see what you did wrong, and suggest ways so you can do it correctly next time.

It might be even better if noone re-distributes non-redistributable files through the board.

Noone ever heard of hashing a file (let's say MD5) to check if it's the same as another one? :unsure:

jaclaz

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Thanks all. Here my bootmgr after modify. I don't know what did I do wrong ?

Bootmgr.rar

Edited by congnt92
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@congnt92

You did nothing wrong, you edit it correctly.

But still i can't reproduce your problem.

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thanks JFX. Now, I think I should be content with what I already have because the error does not affect the installation process. Thanks again, JFX.

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Here you have the addresses for bootmgr.exe version 6.3.9600.16384 (RTM)

0000065E: 0F 900000065F: 88 9000000660: AE 9000000661: 02 9000000662: 00 9000000663: 00 900002B1C1: 74 EB0002B1EB: 75 EB

At address 8AF90 you have the \Boot\BCD string that you can change.

@Mods

Maybe this topic would be better places in WinPE or Multi boot sub forum.

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Just wanted to thank JFX :thumbup for providing a working compiled bmzip.exe and clear, easy to follow, instructions on it's use.  :)

 

It took me some (too much :() time to FAIL :w00t::ph34r: in replicating with the tools provided directly or indirectly here:

http://reboot.pro/topic/16915-bootmgr-recompiler/

and all of 3 (three) minutes to succeed   :yes: with the version of the tool JFX provided.

 

 

jaclaz

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JFYI, instead of PEChecksum.exe one can also use Unsigntool.

It strips the no longer needed digital signature and fixes the PE Header checksum.

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So for everyone how doesn't like command line or hex editing, I've updated my old zbootmgr tool.

 

http://1drv.ms/1plzVcu

Edited by JFX
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