diff --git a/index.js b/index.js
index bf4d39b38..b6fe4ec33 100644
--- a/index.js
+++ b/index.js
@@ -135,6 +135,7 @@ async function start() {
         // Validate settings
         const settings = require('./dist/util/settings');
 
+        settings.write(); // trigger initial writing of `ZIGBEE2MQTT_CONFIG_*` ENVs
         settings.reRead();
 
         const settingsMigration = require('./dist/util/settingsMigration');
diff --git a/lib/util/settings.ts b/lib/util/settings.ts
index 13f0d0a45..96ae6682a 100644
--- a/lib/util/settings.ts
+++ b/lib/util/settings.ts
@@ -146,10 +146,12 @@ function parseValueRef(text: string): {filename: string; key: string} | null {
     }
 }
 
-function write(): void {
+export function write(): void {
     const settings = getPersistedSettings();
     const toWrite: KeyValue = objectAssignDeep({}, settings);
 
+    applyEnvironmentVariables(toWrite);
+
     // Read settings to check if we have to split devices/groups into separate file.
     const actual = yaml.read(CONFIG_FILE_PATH);
 
@@ -277,7 +279,6 @@ export function validate(): string[] {
 
 function read(): Partial<Settings> {
     const s = yaml.read(CONFIG_FILE_PATH) as Partial<Settings>;
-    applyEnvironmentVariables(s);
 
     // Read !secret MQTT username and password if set
     const interpretValue = <T>(value: T): T => {
diff --git a/test/settings.test.ts b/test/settings.test.ts
index 8b159de1f..a850155db 100644
--- a/test/settings.test.ts
+++ b/test/settings.test.ts
@@ -38,7 +38,7 @@ describe('Settings', () => {
 
     const clearEnvironmentVariables = (): void => {
         for (const key in process.env) {
-            if (key.indexOf('ZIGBEE2MQTT_CONFIG_') >= 0) {
+            if (key.startsWith('ZIGBEE2MQTT_CONFIG_')) {
                 delete process.env[key];
             }
         }
@@ -104,17 +104,16 @@ describe('Settings', () => {
         expect(s).toStrictEqual(expected);
     });
 
-    it('Should apply environment variables', () => {
-        process.env['ZIGBEE2MQTT_CONFIG_SERIAL_DISABLE_LED'] = 'true';
-        process.env['ZIGBEE2MQTT_CONFIG_ADVANCED_CHANNEL'] = '15';
-        process.env['ZIGBEE2MQTT_CONFIG_ADVANCED_OUTPUT'] = 'attribute_and_json';
-        process.env['ZIGBEE2MQTT_CONFIG_ADVANCED_LOG_OUTPUT'] = '["console"]';
-        process.env['ZIGBEE2MQTT_CONFIG_MAP_OPTIONS_GRAPHVIZ_COLORS_FILL'] =
-            '{"enddevice": "#ff0000", "coordinator": "#00ff00", "router": "#0000ff"}';
-        process.env['ZIGBEE2MQTT_CONFIG_MQTT_BASE_TOPIC'] = 'testtopic';
-        process.env['ZIGBEE2MQTT_CONFIG_MQTT_SERVER'] = 'testserver';
-        process.env['ZIGBEE2MQTT_CONFIG_ADVANCED_NETWORK_KEY'] = 'GENERATE';
-        process.env['ZIGBEE2MQTT_CONFIG_DEVICES'] = 'devices.yaml';
+    it('Should apply environment variables as overrides', () => {
+        process.env.ZIGBEE2MQTT_CONFIG_SERIAL_DISABLE_LED = 'true';
+        process.env.ZIGBEE2MQTT_CONFIG_ADVANCED_CHANNEL = '15';
+        process.env.ZIGBEE2MQTT_CONFIG_ADVANCED_OUTPUT = 'attribute_and_json';
+        process.env.ZIGBEE2MQTT_CONFIG_ADVANCED_LOG_OUTPUT = '["console"]';
+        process.env.ZIGBEE2MQTT_CONFIG_MAP_OPTIONS_GRAPHVIZ_COLORS_FILL = '{"enddevice": "#ff0000", "coordinator": "#00ff00", "router": "#0000ff"}';
+        process.env.ZIGBEE2MQTT_CONFIG_MQTT_BASE_TOPIC = 'testtopic';
+        process.env.ZIGBEE2MQTT_CONFIG_MQTT_SERVER = 'testserver';
+        process.env.ZIGBEE2MQTT_CONFIG_ADVANCED_NETWORK_KEY = 'GENERATE';
+        process.env.ZIGBEE2MQTT_CONFIG_DEVICES = 'devices.yaml';
 
         const contentDevices = {
             '0x00158d00018255df': {
@@ -125,6 +124,7 @@ describe('Settings', () => {
 
         write(configurationFile, {});
         write(devicesFile, contentDevices);
+        expect(settings.write()); // trigger writing of ENVs
         expect(settings.validate()).toStrictEqual([]);
 
         const s = settings.get();
@@ -147,6 +147,11 @@ describe('Settings', () => {
         expected.advanced.network_key = 'GENERATE';
 
         expect(s).toStrictEqual(expected);
+
+        settings.set(['advanced', 'channel'], 25);
+
+        expect(settings.get().advanced.channel).toStrictEqual(15);
+        expect(read(configurationFile)).toMatchObject({advanced: {channel: 15}});
     });
 
     it('Should add devices', () => {