LG G4 : How to decrypt .dm files on lg G4

[AC Question]

Hi there, my LG G4 has been dead for several weeks because of the boot loop issue.
Basically it's dead.
Before it's dead, I have some pictures and videos saved on my external memory that I locked using the option from the LG G4 Gallery.
Is there a way that I can decrypt / restore my locked files (.dm extension)? or Can I just unlock it using different LG G4 phones ?

Note :
Tried to rename it (does't work)
Tried to open it using some viewer app (doesn't work)

Thank You

 

[dpham00]

Mod Note, I will move this to the g4 forum for more visibility