fix idempotency gne port uctoff

backend/services/control/exporter_monolith.py

@@ -340,8 +340,14 @@ def _drop_registers_matching_last_verified(
                 continue
             # reg179: porovnáváme jen bits0–1 maskou 0x0003 (masked RMW zachovává ostatní bity).
             if int(reg) == 179 and _deye_reg179_verify_match(int(val), int(lv)):
-                skipped.append(int(reg))
-                continue
+                # GEN cutoff (BA81): chceme na zařízení dostat "clean" hodnotu 2/3.
+                # Pokud minulý verified stav obsahuje jiné bity (např. 0xFFFE/0xFFFF),
+                # maska sice sedí, ale firmware/UI nemusí cutoff aplikovat správně.
+                # Proto reg179 skipneme jen tehdy, když je poslední verified hodnota už
+                # skutečně 2 nebo 3 (tj. clean value), ne jen maskově ekvivalentní.
+                if int(lv) in (REG179_MI_EXPORT_DISABLE, REG179_MI_EXPORT_ENABLE):
+                    skipped.append(int(reg))
+                    continue
             if int(lv) == int(val):
                 skipped.append(int(reg))
                 continue

backend/tests/test_drop_registers_matching_last_verified.py

@@ -21,9 +21,17 @@ def test_drop_registers_keeps_reg178_when_mask_differs():
     assert skipped == []
 
 
-def test_drop_registers_skips_reg179_when_mask_matches():
-    registers = [(179, "control_board_special_1", 2)]  # bits0–1 = 2 (cutoff ON)
-    last_verified = {179: 0x1236}  # ...0110b => bits0–1 still == 2
+def test_drop_registers_keeps_reg179_when_mask_matches_but_not_clean():
+    registers = [(179, "control_board_special_1", 2)]  # want cutoff ON (clean value)
+    last_verified = {179: 0x1236}  # bits0–1 still == 2, but not a clean 2/3 value
+    out, skipped = _drop_registers_matching_last_verified(registers, last_verified)
+    assert out == registers
+    assert skipped == []
+
+
+def test_drop_registers_skips_reg179_when_clean_value_matches():
+    registers = [(179, "control_board_special_1", 2)]  # want cutoff ON (clean value)
+    last_verified = {179: 2}  # already clean cutoff ON
     out, skipped = _drop_registers_matching_last_verified(registers, last_verified)
     assert out == []
     assert skipped == [179]