diff --git a/scripts/install b/scripts/install
index 2217b28..ceccbbb 100755
--- a/scripts/install
+++ b/scripts/install
@@ -119,8 +119,8 @@ ynh_script_progression --message="Configuring system user..." --weight=1
 
 # Create a system user
 ynh_system_user_create --username=$app
-#allow user to access USB / serial port to communicate with tools (RFXtrx, Z-wave dongle, etc.)
-usermod -a -G dialout $app
+#allow user to access USB / serial port to communicate with tools (RFXtrx, Z-wave dongle, etc.) & i2c bus
+usermod -a -G dialout i2c $app
 
 #allow app user to restart service on startup
 cp ../conf/sudoer ../conf/$app.conf
diff --git a/scripts/restore b/scripts/restore
index 165a767..7869b0a 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -76,8 +76,7 @@ ynh_script_progression --message="Recreating the dedicated system user..." --wei
 
 # Create the dedicated user (if not existing)
 ynh_system_user_create --username=$app
-#allow user to access USB / serial port to communicate with tools (RFXtrx, Z-wave dongle, etc.)
-usermod -a -G dialout $app
+
 
 
 #Restore user authorization to restart server
@@ -92,6 +91,9 @@ ynh_restore_file --origin_path="/etc/sudoers.d/$app"
 #chown -R root: $final_path
 #Both folder and database file must be own by app user for domoticz to work and allow internal upgrade
 chown -R $app: $final_path
+#allow user to access USB / serial port to communicate with tools (RFXtrx, Z-wave dongle, etc.) & i2c bus
+usermod -a -G dialout i2c $app
+
 
 #=================================================
 # SPECIFIC RESTORATION
diff --git a/scripts/upgrade b/scripts/upgrade
index cc4a906..557d845 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -174,6 +174,8 @@ ynh_script_progression --message="Making sure dedicated system user exists..."
 
 # Create a dedicated user (if not existing)
 ynh_system_user_create --username=$app
+#allow user to access USB / serial port to communicate with tools (RFXtrx, Z-wave dongle, etc.) & i2c bus
+usermod -a -G dialout i2c $app
 
 #allow app user to restart service on startup
 cp ../conf/sudoer ../conf/$app.conf