Win 10 dual boot with partition clone

I tried to copy the current system to an external USB disk (backup / restore). Same problem. I think it's the BCD and the drive letters. It is possible that easyBCD will translate drive letters into internal partition designations (numbered hard disks / partitions). If I duplicate the system, the BCD is also copied. He still points to C. Then when I boot from the external disk, it reads the system-reserved from there, but then starts C on the internal disk. The attempt to make a second menu entry fails, because I take e.g. K from the point of view of the standard system, then when starting from the external hard drive it might be D or E or something else. There is no way to enter something like HD(8)Partition(1) instead of the drive letter in easyBCD. Or is that possible somehow?
 
There are no drive letters in the BCD, The partitions are addressed by a unique ID which is a hash of the device serial number and the offset of the partition from the disk start.
Because that UID is very user unfriendly and prone to typing errors when specifying, EasyBCD translates that UID into a disk letter by using the registry device map on the running system.
That means if you are seeing the device you're trying to boot as "X" on the running OS, you point EasyBCD to X when you add the BCD entry for it. It doesn't matter what the device is going to be when it's booted. EasyBCD will look up X in the registry map and create the correct UID in the BCD.
When you successfully boot the new OS and it's running as C, looking in the BCD with EasyBCD, it will find the UID in the new OS's device map and translate that same entry as "C".
Each OS has its own unique device map and there's no guarantee that there will be any similarity between them, especially if you're plugging and removing devices. Windows allocates disk letters dynamically during the plug and play detection section of the boot process in the order that it encounters devices, unless you've previously used Disk Management's "assign letter" function on a previous boot. In that case the letter is already allocated in the registry map and Windows allocates those letters first before proceding to do the rest in alphabetic sequence as it finds them.
 
Back
Top