We started seeing HW4 vehicles getting the same FSD Beta version as HW3 vehicles
as early as May with 11.4.x, so presumably Tesla figured out some way to share the model between hardware potentially as you suggest with cropping and binning. This inclusion of HW4 was a 2 month delay after HW3 got any 11.x back in March, but most of
HW4 fleet had to wait until late August for wide release of 11.4.4 -- 3 months after initial HW4 release and basically 6 months after HW3.
Perhaps we'll initially see a similar shared model between HW3 and HW4 for end-to-end with the compatibility hacks/solutions, and maybe the model will even be tainted/trained with HW4-simulated-as-HW3 inputs. Unclear if end-to-end will be more sensitive to artifacts introduced by supporting both sets of cameras than 11.x.
So unclear if Elon Musk's "
HW4 software will lag HW3 by at least another six months" is referring to even getting the compatibility working with end-to-end or potentially the longer-term goal of dedicated HW4 model trained with full HW4 cameras making use of HW4 compute.