Hello,
I tested and witnessed that iceprog can’t write to the CuV2.
I checked the source code and it does the write enable command just like Labs does so it’s a mystery…
The good news is that I have two alternatives :
I tried with openfpgaloader instead and it works perfectly fine 
openfpgaloader --verify -b ice40_generic <your bin>
If you have Labs installed, you can program the board using CLI :
alchitry load -f -b CuV2 --bin <your bin>