[cafxx]

Sure, but as I mentioned it has absolutely nothing to do with the CRC calculation, that is what you claimed.

[Kuinox]

Without CRC calculation you could just check which square correspond to which letter and possibly change the letter casing. But with CRC it will leads to squares changing in the CRC area.

[cafxx]

Yes, that's the whole point. I did not claim you can control every single module in the QR. I just said that you can get different QR codes for the same semantic content.