Dual boot pe UEFI cu LVM

Am deja Arch Linux instalat, partitiile sunt facute cu LVM, totu bine si frumos. Am incercat sa instalez in paralel o distributie de pen-testing si anume Parrot OS. Am rupt 100 GB dintr-un LV, si am facut alte doua, unul pentru partitia de boot si unul pentru root (root-ul l-am facut criptat). Am instalat distro-ul, am dat reboot, totu parea sa fie ok. Mi-a creat inca un entry in meniul de boot de la UEFI pentru ce a instalat, dar apare urmatoarea problema:

• Daca boot-ez pe entry-ul de la Parrot OS, imi apare GRUB-ul cu cele doua OS-uri, dar niciunul nu boot-eaza, la Arch linux iau kernel panic 'Kernel panic - not synching:VFS:Unable to mount root fs on unknown-block(0,0)', iar la Parrot OS iau freeze dupa ce bag parola pentru decriptarea partitiei root.
  
• Daca boot-ez pe entry-ul de la Arch, imi detecteaza doar Arch-ul, dar macar asta merge. Am incercat din Arch sa dau un os-prober si grub-mkconfig, dar nu imi detecteaza Parrot OS (da, am montat partitiile inainte sa rulez comenzile alea)

Deci cine imi da o idee cum fac sa imi detecteze celalalt OS? Am mai incercat aceasi instalare si cu Kali si am ajuns in aceasi dilema, deci nu e de la distro, fac eu ceva gresit cu siguranta.
O sa las aici cum arata LVM-ul, numele partitiilor e foarte sugestiv:

[root@NoPlaceLikeHome littlewho]# pvdisplay
  --- Physical volume ---
  PV Name			   /dev/sdb
  VG Name			   HDDgroup
  PV Size			   931.51 GiB / not usable 1.71 MiB
  Allocatable		   yes (but full)
  PE Size			   4.00 MiB
  Total PE			  238467
  Free PE			   0
  Allocated PE		  238467
  PV UUID			   MpeOP4-MqkO-qWbf-F17l-05AD-332Y-F5PudZ
  
  --- Physical volume ---
  PV Name			   /dev/sda2
  VG Name			   SSDgroup
  PV Size			   213.00 GiB / not usable 4.00 MiB
  Allocatable		   yes (but full)
  PE Size			   4.00 MiB
  Total PE			  54527
  Free PE			   0
  Allocated PE		  54527
  PV UUID			   wGLESU-eceO-etAf-BGE5-Q2rs-B8yN-pEEK6q
  
[root@NoPlaceLikeHome littlewho]# lvdisplay
  --- Logical volume ---
  LV Path				/dev/HDDgroup/swap
  LV Name				swap
  VG Name				HDDgroup
  LV UUID				DfhbC8-GE8Q-qtdz-ORFp-SZZT-doIi-2bOyG6
  LV Write Access		read/write
  LV Creation host, time archiso, 2017-08-08 12:37:24 +0300
  LV Status			  available
  # open				 0
  LV Size				16.00 GiB
  Current LE			 4096
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:0
  
  --- Logical volume ---
  LV Path				/dev/HDDgroup/var
  LV Name				var
  VG Name				HDDgroup
  LV UUID				iUMC5N-dYio-uczQ-0LI1-y0lU-CQUt-uR1b21
  LV Write Access		read/write
  LV Creation host, time archiso, 2017-08-08 12:38:58 +0300
  LV Status			  available
  # open				 1
  LV Size				16.00 GiB
  Current LE			 4096
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:1
  
  --- Logical volume ---
  LV Path				/dev/HDDgroup/home
  LV Name				home
  VG Name				HDDgroup
  LV UUID				0pWRRP-AHIu-U2Kh-gwWk-M8w4-pYJb-U5yXmz
  LV Write Access		read/write
  LV Creation host, time archiso, 2017-08-08 12:39:06 +0300
  LV Status			  available
  # open				 1
  LV Size				500.00 GiB
  Current LE			 128000
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:2
  
  --- Logical volume ---
  LV Path				/dev/HDDgroup/data
  LV Name				data
  VG Name				HDDgroup
  LV UUID				UTroId-uCBJ-K2Cl-0CXP-DfB4-z4ZY-7dAa27
  LV Write Access		read/write
  LV Creation host, time archiso, 2017-08-08 12:39:16 +0300
  LV Status			  available
  # open				 1
  LV Size				300.01 GiB
  Current LE			 76803
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:3
  
  --- Logical volume ---
  LV Path				/dev/HDDgroup/parrot-boot
  LV Name				parrot-boot
  VG Name				HDDgroup
  LV UUID				eIdPQJ-DF6I-dXfc-IJpZ-CSRj-DmBF-ji1NNn
  LV Write Access		read/write
  LV Creation host, time parrot, 2017-11-13 15:12:36 +0200
  LV Status			  available
  # open				 0
  LV Size				<1.71 GiB
  Current LE			 437
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:4
  
  --- Logical volume ---
  LV Path				/dev/HDDgroup/parrot
  LV Name				parrot
  VG Name				HDDgroup
  LV UUID				ymqrvt-tY2i-94fU-FSf9-IaM3-c2j3-qnd2OY
  LV Write Access		read/write
  LV Creation host, time parrot, 2017-11-13 15:12:47 +0200
  LV Status			  available
  # open				 0
  LV Size				97.79 GiB
  Current LE			 25035
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:5
  
  --- Logical volume ---
  LV Path				/dev/SSDgroup/root
  LV Name				root
  VG Name				SSDgroup
  LV UUID				HK286o-amGs-t9dy-npi6-PQc6-5alo-sFArMt
  LV Write Access		read/write
  LV Creation host, time archiso, 2017-08-08 12:35:33 +0300
  LV Status			  available
  # open				 1
  LV Size				<213.00 GiB
  Current LE			 54527
  Segments			   1
  Allocation			 inherit
  Read ahead sectors	 auto
  - currently set to	 256
  Block device		   254:6
  
[root@NoPlaceLikeHome littlewho]#

Mersi!