External module WorkItem not getting cycles on cube

The px4_sitl config runs my external module and it gets cycles, but the px4_fmu-v3_default.px4 image loaded on Black cube doesn’t.

px4_sitl looks good:

pxh> ai_vtol_att_control start
pxh> ai_vtol_att_control status
INFO  [ai_vtol_att_control] Running
vtol_att_control: cycle: 3898 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
pxh> listener fake_vtol_vehicle_status

TOPIC: fake_vtol_vehicle_status
	timestamp: 105384000  (0.000000 seconds ago)
	vtol_in_rw_mode: True
	vtol_in_trans_mode: False
	in_transition_to_fw: False
	vtol_transition_failsafe: False
	fw_permanent_stab: False

px4_fmu-v3 has the external module, but it doesn’t get cycles and never publishes (WorkItem::Run impl is what would publish):
Screenshot 2021-01-04 180024

Can anyone suggest why the difference between sitl and hitl?

(Unfortunately, I have not succeeded in using gdb/JTAG, yet…)