So the sub address appears to be 02h with a value of 110000 binary to put the 7118E chip into what the datasheet describes as MODE5.

So I figure that the command should be as follows:

/var/hack/iicsetw 0x42h 0x2h 48

However this yields precisely no discernable impact that I can see. Now there might be other registers involved (and I have a few suspects) but I figure I must be doing something wrong for it to have no impact whatsoever (and I get the right output from iicsetw to know that it is working in itself).

btw: One thing I am worried about is that the 7118 likely gets reset on channel changes, and perhaps even more frequently. But I was still expecting to see some sort of change, even if fleeting!