Well, even shorter then:
- When in doubt, check your code.
- Coppershade, HRM, and WinUAE are correct.
- Providing code and expected result will give you quick answers here.
The order of operation of the Blitter is provided in the HRM and on Coppershade. Correct code to initialize the Blitter is provided on Coppershade.
If you ask again here, please provide helpful information.