Before my unit died, expo_iso at 0x80e5590c was working for me. The display of ISO value changed correctly as light was controlled.Ok, thanks for that input, @0dan0. I've started to use the BSim plugin with Ghidra and the AE function I was working with before in stock D does seem to have a lot in common with the A/B/C AE function. I'm hopeful with at least that, but I haven't identified the expo_iso address yet.