Seriously low space under 9‰ apps may fail to install even I have free space.

I can't install a large app . In storage settings says :
INTERNAL STORAGE :
Total 8gb
Firmware Rom 2gb( 0 free),
System Rom 1gb (free 0.4 gb),
User Rom 1,97GB(free 200 MB,
Apps are here ) ,
User virtual SD card 2,85(free 1.65 gb)

USER VIRTUAL SD CARD:
Available 1.65 Gb,
Apps 1.3 gb, etc.

EXTERNAL SD CARD:
Total 8gb, available 1,24 Gb
Apps 1,03gb etc.

I have default save location on SD, I have restarted play store, apps are installed on user Rom. When I delete a large app user Rom has more space. I have 1 Gb free on internal and external memory. How to use this memory for default save location and not user Rom (it is only 2 gb), Or how to extend partitions? System is lagging and a notification says I have not free space. Zte v975