hard drive - Diskpart assign letter to partition that is not associated with a volume (windows 10)

I used to have 3 volumes on my disk before something happened to the MBR that messed up my boot.

Now i'm trying to rebuild the boot environment to save all my data but it seems it is all lost. I can see the data through the command promt (from windows 10 DVD)

I am trying to do bcdboot c:\Windows /m {guid} but it is not working

I have also run:

bootrec /fixmbr (success / no error)
bootrec /fixboot (success / no error)
bootrec /rebuildbcd (failes with error "The requested system device cannot be found")

I can find a lot of information on how you assign a drive-letter to a volume, but not how to assign a drive letter to a partition or make a partition associated with a volume.

When selecting the partition through diskpart i 'detail' part tells me: "There is no volume associated with this partition." so i am thinking there must be a way to asscociate it with a volume. but how?

Info:
list disk : 1 entry 465GB 0 B free
list part : 3 entry
part 1 reserved 128MB offset 1024kb <- this used to be my boot-partition
part 2 System   465GB offset 129MB
Part 3 Recovery 450MB offset 465GB
list vol : 3 entry
Vol # LTR
Vol 0 D   UDF DVD-ROM 3894 MB healthy  <- (this is where my 128MB boot part used to be)
VOL 1 C   NTFS Partition 465GB healthy Hidden
VOL 2 E   NTFS Partition 450MB healthy hidden

How do i proceed to recover the boot?