"iocontrol.0.user-enable-out" seems broken in latest 2.9 master

Thank You Chris for all the help. Sorry, but can you be more clear what you mean when you say "you can add estop-out to the external estop chain"? What are the exact hal signal names you are referring to?

Sorry it's hard to be exact as I don't know your hardware or needs.
Based on your HAL file you selected an external estop input (estop-ext)
This says to me you want external hardware to be able to estop linuxcnc.

Usually one wants to be able to estop/reset via the GUI button, but that is not the only option.
Here are some options (sim/axis/classicladder can demo these)

1) just use the gui button (no external estop)
2) just the external estop - gui button will only set the machine off or the button can be removed
3) combined gui and external -comes out of estop immediately when both are cleared
4) combined gui and external with estop reset latch - comes out of estop when both are cleared and gui button is pressed

The chain refers to the software and hardware links.
for option 1 above (standard in the sim configs):

net estop-loop iocontrol.0.user-enable-out iocontrol.0.emc-enable-in


Here is yours (I removed debounce for clarity)

net estop-out <= iocontrol.0.user-enable-out
net estop-out => hm2_7i92.0.7i84.0.0.output-00

net estop-ext => iocontrol.0.emc-enable-in
net estop-ext <= hm2_7i92.0.7i84.0.0.input-00

estop-out is the gui signal sent out to external logic
estop-ext is the input from the logic that actually sets linuxcnc in/out of estop

If you electrically connected hm2_7i92.0.7i84.0.0.output-00 to hm2_7i92.0.7i84.0.0.input-00 The button would work normally.
If you wanted to add a hardware estop button to this, then you would add a switch between them. In that case the gui and the hardware button must be cleared to clear linuxcnc's estop state.

What do you wish to do?