226 replies to this topic

[steve6375]

Check this:

http://www.forensicf...wtopic/t=10162/

possibly the references given there can help.

 

 

Thanks.

The problem is I don't understand how the algorithm works.

consider this:

 

checksum = (checksum<<31) | (checksum>> 1) + data[i];

now if a load of sectors are filled with 0's, then  the + data[i] bit will be 0.

This means we are just ORing two values together after shifting them.

So, after lots of loops where data=0,  the result is bound to be FFFFFFFF  if we shift with rotation, or 00000000 if we shift with zero's in.

So I don't understand how this works to get a decent proper checksum???

[Wonko the Sane]

Thanks.

The problem is I don't understand how the algorithm works.

 

Well, here you are assuming that I actually understand the matter (which I don't ).

 

In my simplicity, we have a tool (open Source) that (supposedly) can make an exFAT filesystem:

https://code.google.com/p/exfat/

https://code.google....wse/trunk/mkfs/

 

I would guess that EITHER it completely fails to create a correct exFAT filesystem OR that it does manage to create one (including the checksum you are talking about).

So, if I were you (and a programmer and  actually capable of understanding C code) I would peek in that code to see how they solved the problem or, even better, "port" the thingy to your tool.

 

Wonko

[steve6375]

OK - sorted! was a problem with shift - it is really a rotate! So this code works fine once you use a rotate instruction!

 

 

Dim xsum As Long
Dim i As Integer
xsum = 0
For i = 0 To (11 * 512) - 1
    If i <> 106 And i <> 107 And i <> 112 Then
        xsum = (Rotate32(xsum, 31) Or Rotate32(xsum, -1)) + SB(i)
    End If
Next

[alacran]

Or take a look how BootIce (also free tool) does it on any system starting with  XP or PE (as I have tested).

 

I tested your 2 ISOS way for XP install using v22 unattended and 4.0PE (just the one make from AIK for Win8 deploy, nothing added) as second ISO on a machine with multicard reader and it fail after formating de internal IDE HDD (160GB disk) first volume (20GB) and reboot, it didn't boot there was a screen:

 

Try (hd0,0): none-MS: skip

Try (hd0,1) : invalid or null

Try (hd0,2) : invalid or null

Try (hd0,3) : invalid or null

Try (hd1,0) : NTFS5 : No grldr

Try (hd1,1) : invalid or null

Try (hd1,2) : invalid or null

Try (hd1,3) : invalid or null

Can not find GRLDR

Press space bar to hold the screen, any other key to boot pevious MBR ...exF

Remove disk or other media.

Press any key to restart.

 

Thinking it is related to multicard reader, I open the case and unplug it. Same thing every time I reboot that machine with the USB pluged I get same screen.

 

I unpluged the internal HDD and put another IDE 10GB (only one partition) and rebooted.  Same thing very time I reboot that machine with the USB pluged I get same screen.

 

Trayed on other machine 80GB IDE HDD (20GB first partition active) and it boots OK from USB, trayed then the XP install.  Same thing every time I reboot that machine with the USB pluged I get same screen.

 

I unpluged the internal HDD and put a second IDE 10GB (only one partition) on second machine and rebooted.  Same thing every time I reboot that machine with the USB pluged I get same screen.

 

If I tray other USB stick on any of them they boot from that USB just fine.

 

I reformated the USB and trayed again in all configurations and no change, Why? the two machines boted fine first time with 160GB HDD first one and 80GB second one, after traying to install they don't boot from HDD or the USB stick with your v22 any more but they boot from any other stick.

 

Best Regards

Edited by alacran, 29 April 2013 - 07:42 PM.

[Wonko the Sane]

alacran 

That you trayed it is likely , that grub4dos printed tray instead of try, is less so.

 

Multicard readers have been traditionally a PITA, I seem to remember similar issues with ilko_t's WinsetupFromUSBwithGUI.

 

Wonko

[steve6375]

Diskpart runs... so what disks does it show

[alacran]

The first time when it booted fine you can see the internal HDD and every partition on it C:, D:, and E:, on the two machines they do have 3 primary partitions each, the one with 160GH HDD has only XP as System and two other partitions for documents, the one with 80GB HDD has multiboot XP and Win7 and a document partition, the C: partition (primary active) was selected for formatting in both when installing and I got the message to select a volume.

 

Forgot to tell you the format finished fine and C: partition changed from C: to D: and all others acordingly (D: to E: and so on, all they have a label to avoid confusions).  On the first one when multicard reader was pluged it said something about can't find source, on the second machine (no multicard reader on it) I got the message to remove the USB and reboot.

 

@ Wonko

 

The post (No. 104) Has been fixed.

Edited by alacran, 29 April 2013 - 07:57 PM.

[steve6375]

I you just format the partition, then the diskpart script (which is displayed) will make the selected volume the active (bootable) volume.

If you re=partition - does it work then?.

[alacran]

Forgot to tell you the format finished fine and C: partition changed from C: to D: and all others acordingly (D: to E: and so on, all they have a label to avoid confusions).  On the first one when multicard reader was pluged it said something about can't find source, on the second machine (no multicard reader on it) I got the message to remove the USB and reboot.

[steve6375]

The partition should be assigned the letter J: after formatting - maybe you have a J: already????

If so, edit runwinnt.cmd to use say W: instead of J:

[alacran]

The USB stick is J: when in Windows (Just cheked) I will change letter to U, is that OK?

[steve6375]

any letter that is free. I guess I should check for a free drive letter rather than fix it as J: - my bad! It was something I meant to change when I first used J: but forgot to change it to a higher letter!

[alacran]

Just changed USB stick to U: and pluged to a machine with 10GB HDD (XP on it) and when booting from USB same screen

Edited by alacran, 29 April 2013 - 08:22 PM.

[alacran]

Is there a minimun size for the HDD in your code?

Edited by alacran, 29 April 2013 - 08:31 PM.

[steve6375]

The diskpart script is displayed on the screen. NTFS will be used by default. 

[steve6375]

You need to replace all J's with %TARGET% in the script - there are 3 or 4 places where I have hardcoded J:!

[alacran]

Just chaged the HDD to 160GB, now when USB pluged (letter U: assigned) it boots from USB again (not before change letter).

Edited by alacran, 29 April 2013 - 08:42 PM.

[alacran]

You need to replace all J's with %TARGET% in the script - there are 3 or 4 places where I have hardcoded J:!

 

Is it in _ISO\E2B\grub? There are many there Wich one?

[steve6375]

post 110  runwinnt.cmd

[alacran]

I can't find runwinnt.cmd Where is it? Or is it created after starting install? remember I reformated the USB stick.

Edited by alacran, 29 April 2013 - 09:55 PM.

[steve6375]

documentation is all in the tutorial 72a - the file is at \_ISO\E2B\firadisk\runwinnt.cmd

[steve6375]

I have modified the runwinnt.cmd file so it uses a free drive letter now - please re-download BETA22 and update your Easy2Boot drive.

[alacran]

I changed all J: for %TARGET% in runwinnt.cmd booted from USB and started the install, before format having F: CD, C: XP, E: documents and D: Easy2Boot.  Selected C: to format and when finished C: was now J: but all other volumes didn't change letter. I got a message saying to remove all USB drives and press any Key to reboot y did it and It didn't reboot used Ctrl+Alt+Del, after reboot I got a message:

 

An operating system wasn't found.

Disconect all drives with no operating system

Reboot using Ctrl+Alt+Del

 

Now I have an I386 folder in USB root with unattend.txt inside.  Any ideas?

Edited by alacran, 29 April 2013 - 11:27 PM.

[steve6375]

You didn't edit all occurences of J - use the new download.

[alacran]

Working fine using very last beta 27v1, just before you relase the final version, Do you have any plans for adding VHD booting?

 

It could be good when booting from USB HDD.

 

Best Regards