Insufficient space, at least that's what the phone says

Help Fairphone 1
4

I have the same problem with my FP1U
I read lot and lot of topic about this problem and I have finally try a hard reset of the FP

But it doesn’t works !!!
After reset, I have installed one app with success and now I have the same error message : “Insufficient storage error”

With my reads, I think have understood this about my FP:

  • the system partition is 1Go
  • the “internal memory” is 13Go
  • in my case I have another SD card with 32Go (external storage)

I don’t undertand why the app goes to the system partition (even if “internal storage” or “external storage” is set).

How can we definitively solve this problem ?