diff --git a/zephcore/adapters/datastore/ZephyrDataStore.cpp b/zephcore/adapters/datastore/ZephyrDataStore.cpp
index 9f46ba0..bd7f60c 100644
--- a/zephcore/adapters/datastore/ZephyrDataStore.cpp
+++ b/zephcore/adapters/datastore/ZephyrDataStore.cpp
@@ -794,6 +794,19 @@ void ZephyrDataStore::loadPrefs(NodePrefs &prefs)
 			prefs.cad_busycap = 90;
 		}
 	}
+
+	/* Offset 159: adc_multiplier (ZephCore extension, float LE, 0 = board
+	 * DT default).  Absent in pre-existing files → keep 0.0 so the DT
+	 * default stays in effect.  Same range guard as the repeater CLI path
+	 * (CommonCLI constrains 0..30000); NaN/garbage resets to default. */
+	if (off + 4 <= len) {
+		memcpy(&prefs.adc_multiplier, &buf[off], sizeof(float));
+		off += 4;
+		if (prefs.adc_multiplier != prefs.adc_multiplier ||
+		    prefs.adc_multiplier < 0.0f || prefs.adc_multiplier > 30000.0f) {
+			prefs.adc_multiplier = 0.0f;
+		}
+	}
 }
 
 void ZephyrDataStore::savePrefs(const NodePrefs &prefs)
@@ -883,7 +896,12 @@ void ZephyrDataStore::savePrefs(const NodePrefs &prefs)
 	buf[off++] = prefs.cad_probe_interval;
 	/* Offset 158: cad_busycap (ZephCore extension, percent) */
 	buf[off++] = prefs.cad_busycap;
-	/* Total: 159 bytes */
+	/* Offset 159: adc_multiplier (ZephCore extension, float LE, 0 = board
+	 * DT default).  Was applied at boot but never serialized before this
+	 * field existed — battery calibration silently reset every reboot. */
+	memcpy(&buf[off], &prefs.adc_multiplier, sizeof(float));
+	off += 4;
+	/* Total: 163 bytes */
 
 	bool ok = atomicReplaceFile(PREFS_FILE, buf, off);
 	LOG_DBG("savePrefs: wrote %s, ok=%d (%d bytes), name='%.16s'",
diff --git a/zephcore/helpers/CommonCLI.cpp b/zephcore/helpers/CommonCLI.cpp
index ce46bc5..b613bdb 100644
--- a/zephcore/helpers/CommonCLI.cpp
+++ b/zephcore/helpers/CommonCLI.cpp
@@ -614,13 +614,26 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
             savePrefs();
             strcpy(reply, "OK");
         } else if (memcmp(config, "int.thresh ", 11) == 0) {
-            _prefs->interference_threshold = atoi(&config[11]);
-            savePrefs();
-            strcpy(reply, "OK");
+            /* Companion runtime never reads this (getInterferenceThreshold is
+             * only overridden in Repeater/RoomServer) — reject instead of a
+             * false OK. */
+            if (strcmp(_callbacks->getRole(), "companion") == 0) {
+                strcpy(reply, "Error: not supported on companion");
+            } else {
+                _prefs->interference_threshold = atoi(&config[11]);
+                savePrefs();
+                strcpy(reply, "OK");
+            }
         } else if (memcmp(config, "agc.reset.interval ", 19) == 0) {
-            _prefs->agc_reset_interval = atoi(&config[19]) / 4;
-            savePrefs();
-            snprintf(reply, CLI_REPLY_SIZE, "OK - interval rounded to %u", ((uint32_t)_prefs->agc_reset_interval) * 4);
+            /* Companion runtime never reads this (getAGCResetInterval is only
+             * overridden in Repeater/RoomServer). */
+            if (strcmp(_callbacks->getRole(), "companion") == 0) {
+                strcpy(reply, "Error: not supported on companion");
+            } else {
+                _prefs->agc_reset_interval = atoi(&config[19]) / 4;
+                savePrefs();
+                snprintf(reply, CLI_REPLY_SIZE, "OK - interval rounded to %u", ((uint32_t)_prefs->agc_reset_interval) * 4);
+            }
         } else if (memcmp(config, "cad.auto ", 9) == 0) {
             if (memcmp(&config[9], "on", 2) == 0 || memcmp(&config[9], "off", 3) == 0) {
                 _prefs->cad_auto = (config[9] == 'o' && config[10] == 'n') ? 1 : 0;
@@ -818,14 +831,21 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
             savePrefs();
             strcpy(reply, "OK (ignored: direct.txdelay is now adaptive)");
         } else if (memcmp(config, "backoff.multiplier ", 19) == 0) {
-            float f = atof(&config[19]);
-            if (f >= 0.0f && f <= 2.0f) {
-                _prefs->backoff_multiplier = f;
-                _callbacks->setBackoffMultiplier(f);
-                savePrefs();
-                strcpy(reply, "OK");
+            /* Companion's setBackoffMultiplier callback is the base-class
+             * no-op and the value isn't restored at boot — reject instead of
+             * a false OK. */
+            if (strcmp(_callbacks->getRole(), "companion") == 0) {
+                strcpy(reply, "Error: not supported on companion");
             } else {
-                strcpy(reply, "Error, range 0.0-2.0");
+                float f = atof(&config[19]);
+                if (f >= 0.0f && f <= 2.0f) {
+                    _prefs->backoff_multiplier = f;
+                    _callbacks->setBackoffMultiplier(f);
+                    savePrefs();
+                    strcpy(reply, "OK");
+                } else {
+                    strcpy(reply, "Error, range 0.0-2.0");
+                }
             }
         } else if (memcmp(config, "owner.info ", 11) == 0) {
             config += 11;
@@ -848,6 +868,12 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
                 strcpy(reply, "Error, must be 0,1, or 2");
             }
         } else if (memcmp(config, "loop.detect ", 12) == 0) {
+            /* Loop detection runs only in the Repeater/RoomServer forward
+             * path — companions never consult loop_detect. */
+            if (strcmp(_callbacks->getRole(), "companion") == 0) {
+                strcpy(reply, "Error: not supported on companion");
+                return;
+            }
             config += 12;
             uint8_t mode;
             if (memcmp(config, "off", 3) == 0) {