Under the Engine configs, you will see a BaseDeviceProfiles.ini. I copied this into my projects Config directory and renamed to DefaultDeviceProfiles.ini, made the changes required:
TextureLODGroups=(Group=TEXTUREGROUP_World,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_WorldNormalMap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_WorldSpecular,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Character,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_CharacterNormalMap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_CharacterSpecular,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Weapon,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_WeaponNormalMap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_WeaponSpecular,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Vehicle,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_VehicleNormalMap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_VehicleSpecular,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Cinematic,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Effects,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=linear,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_EffectsNotFiltered,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Skybox,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_UI,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Lightmap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Shadowmap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,NumStreamedMips=3,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_RenderTarget,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_MobileFlattened,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Terrain_Heightmap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Terrain_Weightmap,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=aniso,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Bokeh,MinLODSize=1,MaxLODSize=256,LODBias=0,MinMagFilter=linear,MipFilter=linear,MipGenSettings=TMGS_SimpleAverage)
+TextureLODGroups=(Group=TEXTUREGROUP_Pixels2D,MinLODSize=1,MaxLODSize=16384,LODBias=0,MinMagFilter=point,MipFilter=point,MipGenSettings=TMGS_SimpleAverage)
Saved and launched the editor and tested my 8192x8192 texture:
