Error 0x4 while partition hiding/unhiding

  • Hi, I am getting the following error: "Error 0x4 while partition hiding/unhiding (disk content unchanged)". I have launched Gujin v2.6 using an external USB CD/ROM into a HP Laptop 6910P. I am trying to boot a windows XP NTFS partition installed inside a HP Multibay II Caddy.

    The HP laptop Bios doesn't allow to boot the HDD installed inside the Multibay caddy so I was trying  to use Gujin to overcome the problem.

    The tool is able to locate the Multibay II HDD partitions. Unfortunately after selecting the partition to boot is returning the following error: 'Error 0x4 while partition hiding/unhiding (disk content unchanged)'. I uploaded a picture:

    Any idea on how to fix this error?

    HP forums thread:


    • Hi,

      At this point, having an error 0x4 means that the booted partition has not been found.
      Basically, to automatically hide/unhide FAT and NTFS partitions, Gujin start with the last extended partition of the last disk, walk backward and unhide all partitions until it finds the booted partition, then hide all partition until the first primary partition of the first disk - the pass is first done read-only to produce error messages with "(disk content unchanged)" in case of error, and exit cleanly.
      Because all the extended partitions of all disks have to be scanned before all the primary partitions, some errors can happen on invalid disks (like a disk with invalid partition table?), the walk backward do not complete and the booted partition is not found.
      I would try two things in your case:
      1- once Gujin has started, remove the CDROM and type ^R to reprobe all disks, maybe Gujin has a problem when seeing a CDROM while hide/unhiding partition (Then I need to fix something in the process)
      2- disable partition hiding/unhiding in Gujin setup (press space in Gujin), I do not think you need this treatment if you only have one Window XP installed and if Window XP is in a primary partition. Gujin setup defaults can be costumised by options of the installer.

      Please report success/failure,

    • The previous screenshot was taken with the following configuration:
      - HP 6910P laptop primary  internal HDD bay: EMPTY NO DRIVE
      - HP 6910P laptop secondary internal HDD bay: LOADED with 320Gb HDD with 2 NTFS partitions (the primary is active)
      Gujin v2.6 loaded from external USB cd rom.

      Now I have the following configuration:
      - HP 6910P laptop primary internal HDD bay: LOADED with 120Gb HDD with ENCRYPETD partition (safeguard easy)
      - HP 6910P laptop secondary internal HDD bay: LOADED with 320Gb HDD with 2 NTFS partitions (the primary is active)
      Gujin v2.6 loaded from external USB cd rom.

      I am getting the following error when Gujin is starting:

      I believe Gujin is trying to recognize the primary internal HDD bay loaded with a no standard MBR due to 'Safeguard Easy' encryption. This process looks like is failing. There is a way to skip this drive when Gujin is starting? I really don't want to reopen the laptop and remove the primary drive for testing the ^R and  partition hiding/unhiding disable options.


    • With the two disks connected, there is a completely different problem: the BIOS crashes (the microprocessor executing code in the BIOS area over 0xF0000000) when Gujin tries to detect which disk are present and their capabilities, or when trying to read some sectors to detect if disks have partitions.
      I am really not sure that it is an encryption problem, mostly if the encryption software (I do not know yours) is encrypting partition independantly.
      For you to sort out this problem, I would advise to boot from a read/write media like a floppy or USB thumb drive with Gujin installed so that you can easily (on another PC) disable "hiding/unhiding" and "BIOS disk probe" checkboxes, save it into Gujin configuration by enabling "disk write" checkbox, and boot your laptop with this Gujin. There is no way to skip a drive in Gujin.
      For me to sort out this BIOS crash (if possible at all in Gujin), I would need the DBG file written by dbgdisk.exe in standard-2.6.tar.gz. You would need to have a bootable DOS floppy disk or USB thumb drive (later can be produced by HPUSBFW.EXE found on Internet).


    • I think Gujin is failing when trying to read some sectors from the internal encrypted HDD to detect if disks have partitions. With 'Utimaco Safeguard Easy' installed the entire drive from the outside is completely hidden. Check if the following screenshot taken from 'Active NTFS Reader' could help you:

      I will run the HPUSBFW and get the DBG file for you later this week. I will also try to deploy Gujin into a USB drive and change the configuration.


    • Thanks for the screenshoot, but Gujin should be able to handle unreadeable MBR, invalid MBR or even hard disk powering in standby mode - I have tested most of these configurations (even if I do not re-test everything at each release).
      Gujin can also handle the BIOS crashing in some cases (installing a recovery handler instead of the default handler which displays the crash dump), but that can lead to unstable BIOS services after the crash - so it is better to try to detect why that BIOS will crash and do not request the BIOS service at all in that case.
      That is why I need the DBG file: to try to find which BIOS call crash, and try to find an obvious pattern which tell Gujin to disable probing this disk with BIOS.
      That is also why you can disable BIOS disk probing altogether, and use only IDE.


    • Here you go, the DBG file for the HP6910P:
      I tried disabling "hiding/unhiding" and "BIOS disk probe" check boxes but I am getting the following:

      "Exiting GUJIN without error.........

      A disk read error occurred
      Press Ctrl+Alt_del to restart


    • OK, thanks for the DBG file.

      It seem simply that the BIOS of your PC do not recognise at all the Multibay caddy (I do not know why), and Gujin has no problem with it. So for Gujin everything happen as expected, so the message "Exiting GUJIN without error........." but when Windows starts (Windows absolutely needs a working BIOS disk to start, unlike Linux), it cannot find it and displays "A disk read error occurred Press Ctrl+Alt_del to restart".
      I assume that the hard disks are present in the Multibay caddy before you are powering up the computer, so that your BIOS has no reason not to find them. Maybe try to find a way to upgrade your BIOS at HP website.

      The only way to get your setup working using Gujin would be for the bootloader to provide that BIOS to windows, and Gujin do not do that: after all it is a bootloader and not a BIOS replacement.
      The main problem to implement this "BIOS for window" is where to place these assembly instructions in the memory, because when DOS or windows start-up they assume they own all the memory - there isn't any way to tell that some part of the real-mode addressable memory is reserved.

      I still do not know why Gujin crashed with your encrypted disk, I was waiting for a crash report in the DBG file and there isn't any. If you had some time, could you redo the process to produce the DBG file, but this time go to the "setup" screen of Gujin and tick the box about probing IDE interface (the checkbox is grayed but still tickable for dbgdisk.exe) then go back to the main screen and type Control R to reprobe all disk: that may produce this crash and a usefull DBG file, to improve Gujin.

      Sorry not to be able to help much here,

    • I already updated the firmware without luck :(

      At this point.... I give up on booting from Multibay. HP Bios Really sucks!!!!!   HP Support people also really sucks!!!!!!

      Thanks a lot for all the help on sorting out this issue.