My original ET-4 card had 2.14 F/W and dated 6/0915. I sent it to Tom to have the F/W updated and it is now 2.16.. Tom did not mention that he installed a resister, so I really doubt he did, as we talked about it quite a bit.. I just checked the board and both resisters are there and the solder does not look disturbed.
If I remember correctly, before the upgrade, if you pushed a button on the main panel it would turn on the light below the button # even if it was 4 through 7.. But before the upgrade you could only see Aux 1 -3 in the circuits list.. After the upgrade you could see Aux 1 -7.
It has been a while and I have slept since then..
Either way, if it works, it works.. I'd want to make sure the you can see all the circuit numbers.. The screenshot below was before the F/W upgrade
I guess my point is that you already had 2.16 and no resistor.. I had 2.14 and had the resistor.. But we both had the ET-4.. When you added the resistor you got the ET-8, and when I upgraded the F/W to 2.16 I got the ET-8... So "maybe" Pentair has changed how they control the ET-4 to ET-8 switch.. and that maybe why your resistor looked like it was clipped off.. it would be cheaper to manufacture all the cards as the ET-8 and just clip the resistor to switch back to the ET-4.. Just guessing of course..
I am sure the Tom can tell us if he ever shows up again...
The resistor thing is correct... I think earlier versions had separate firmware forks, which may have required the hardware AND firmware change, but at some point they merged (I think I noticed this as of 2.130?) so you can "upgrade" any board by just adding the right resistors. *Note that the earliest ET boards had a smaller chip that won't take the current firmware.
Similar tricks exist to make a "Lite" indoor or wireless controller into a regular one, I haven't posted anything about it here for fear of legal reprisal against TFP, but pm me if you're interested.
Hardware manufacturers have been doing this sort of thing for ages - it's super cost effective although it can be construed as somewhat deceitful? maybe? I dunno... it IS their proprietary information afterall, so it's probably appropriate to not shout it from the rooftops considering the state of the right to repair laws these days
The firmware scans the pins that those resistors are connected to, and detects a high or a low to set the board type. When I was messing with this I would take an ET-8, cut one of the resistor legs, reset it, and it would become a 4. It was fun!
And for lites - if my memory serves me, there's a jumper where the old phone adapter? connected that you need to cut. And voila, you have an 8. The lite also used to have it's own firmware but now it's all the same binary as the 4/8