[trouble getting bootloader installed - stuck in chroot]

Thank you foxoswin! 
thank you for your help. Unfortunately i am not at this computer until Sat/Sun, so i can't check that out soon. 

[trouble getting bootloader installed - stuck in chroot]

Hi there,

i'm having severe trouble getting the bootloader installed. After issued a wrong command for installing the bootloader i'm getting:
 

Grub loading..
Welcome to GRUB!
Attempting to decrypt master key...
Enter passphrase for hd2,msdos2 (2eac0b65743546508bc76834698d70f8):

The passphrase i used to encrypt my lvm doesent work. And even when i try booting an win-recovery-usb-boot-media the same message appears... *confused*

Also,  according to my BIOS-settings i should be booting in bios-mode. But according to systemrescuecd-x86-5.2.2.iso booting into a black/white-menue-screen means i was booting into UEFI??

*even more confused* How can the cd boot inUEFI mode even if it is not turned on in BIOS??

I want to dual boo a win10 which was already installed on sda2 in non-UEFI-mode... i have my partitions set up like this:

 

AME                    MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
loop0                     7:0    0 469,9M  1 loop  
sda                       8:0    0 238,5G  0 disk  
├─sda1                    8:1    0   500M  0 part  
├─sda2                    8:2    0 100,8G  0 part  
├─sda3                    8:3    0   470M  0 part  
└─sda4                    8:4    0 136,7G  0 part  
sdb                       8:16   0   2,7T  0 disk  
├─sdb1                    8:17   0   1,3T  0 part  
├─sdb2                    8:18   0     1M  0 part  
├─sdb3                    8:19   0   369G  0 part  
├─sdb4                    8:20   0   511M  0 part  
├─sdb5                    8:21   0 100,5G  0 part  
├─sdb6                    8:22   0 254,2G  0 part  
├─sdb7                    8:23   0 699,3G  0 part  
└─sdb8                    8:24   0    16G  0 part  
sdc                       8:32   0 223,6G  0 disk  
├─sdc1                    8:33   0  16,4G  0 part  
└─sdc2                    8:34   0 207,2G  0 part  
  └─lvm                 253:0    0 207,2G  0 crypt 
    ├─funtoovg-swap     253:1    0    16G  0 lvm   
    ├─funtoovg-lvolroot 253:2    0    60G  0 lvm   /
    └─funtoovg-lvolhome 253:3    0 131,2G  0 lvm   /home
sr0                      11:0    1 545,8M  0 rom   

 

but when i tryed to: boot-update i got: 

FileNotFoundError: [Errno 2] No such file or directory: '/boot/grub/fontsunicode.pf2'

or if i tryed:  grub-mkconfig -o /boot/grub/grub.cfg
 

.
.
.
 /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
Linux-Abbild gefunden: /boot/kernel-debian-sources-x86_64-4.14.12-2
initrd-Abbild gefunden: /boot/initramfs-debian-sources-x86_64-4.14.12-2
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
.
.
. 
  /run/lvm/lvmetad.socket: connect failed: Datei oder Verzeichnis nicht gefunden
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
Ubuntu 16.04.4 LTS (16.04) auf /dev/sda4 gefunden
Ubuntu 16.04.4 LTS (16.04) auf /dev/sdb3 gefunden
Ubuntu 16.04.4 LTS (16.04) auf /dev/sdb5 gefunden
Ubuntu 16.04.4 LTS (16.04) auf /dev/sdb7 gefunden
erledigt

so i'm totally confused about which boot method i should use and still stuck in chroot (even though i still can chroot into my encrypted system) but of course am not able to boot/fix windows...

I searched the net already for too long, but confusion doesn't end... and don't know what to do any more... :( could someone help please?

Many thanks for any help in advance.
Aloha