Proven utility for changing Drivers letter for NT4 ?

[ruthan]

Hello,
does some know some proven utility for NT4? 
There is in build Disk utility, but for some reason it reports even some not system drivers as locked, there is not even swap on them so i dont understand how to unlock them. There is option to change letter after reboot, but its not working at least in some cases (on my system it worked, sometimes i needed a few trie, but now it stopped to work for some reason.. - im not sure if preboot partition mapping tools are actually executed.. - maybe bootmanager (Grub4Dos->Plop->EasyBCD) make difference and some sequence is skipped.. ) - letters are still the same after reboot, when i remove letter not assign them, after reboot are still drive letters mapped.
    I have tried Acronis partition tools, again they require reboot and nothing is changed, my guess is they simply count on Windows 2000+ solution.
    I have tried some old Paragon tools which i own, but it seems the same..  On more modern version there is something like force disk disconnection and force drive letter change without reboot, but in case of old tools still compatible with NT4 this is missing.

More modern Windows are using these registry path for it:
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
  Its not available in Windows NT4.
  I have found, something there:  HKEY_LOCAL_MACHINE\SYSTEM\DISK 
   - there some Information key, which are probably related to some partitions, but there is not some letter to which they are mapped.. Maybe its some binary / hex part of this value.. 
  Other problem is there are just 2 values, i have like 7 partitions, just order these Informantion keys are used to map it for first entry to first free drive letter, second to second etc.. These keys are 920 character in size - its byte. Samples attached.
   I found driver letter character inside, so i have tried little switcheroo by replacing letters for intended, D for Z etc, but did not worked, good news its machine is still booting... What is interesting changes are lost.. So it looks like these values are somehow generated during the boot, or simply click on ok, after letter change in the right column is not enough..  I have tried to change both Info* keys.

  Maybe its possible to some trick like force cd driver letter to free some drive letter and use remove it and assign it after.. Or maybe disable physical disk device, if its not primary boot device.
  For Windows 98 there is drive letter assigner, but so far i did not found something for Windows NT4.

  I doubt that some boot cd could to do the same, because it would imply that NT4 hive would be loaded to write there changes.
  Because one disk is SCSI array i cant simply disable it - on bios level to make changes step by step.. Or not easily SCSI array settings are pretty limited and i can maybe do it, through special RAID manager boot cd menu.. Still, i would prefer some working Windows utility to do it..

  I looked for some key in the registry, but i have found only keys for optical drives. 

NT4DiskKeys.7z

Edited June 16 by ruthan