How to turn off texture compression on mobile Cardboard VR application?

Hello. I’ve got a problem with texture compression on mobile VR (Cardboard). My 360 is made of cube with 6 4096x4096 lightly compressed textures. Screens below show the view on mobile preview on 1920x1080 laptop screen:

Unfortunately on screenshots made on LG G4 with 2560x1440 resolution the pictures are blurry and heavily compressed. On white wall and doors there can be seen ugly “compression curves” and the last image shows closeup comparison between mobile preview and Cardboard view to show the quality downfall and lost detail:

192045-screen3.png

I’ve tried to set r.MobileContentScaleFactor = 2 on every Android profile in Device Profiles, but that didn’t change a thing. I’ve also tried to turn mipmapping off, but that only made everything oversharped which was worse.

Because I can’t accept this quality in case of VR application my question is, how can I get rid of this compression completely?