Update README

README.md

@@ -2,13 +2,19 @@ SPayToGPay
 ============
 
 A helper app to remap the Samsung Pay button shortcut on the
-Galaxy Watch 4 to Google Pay on watches in regions shipping
-without Samsung Pay.
+Galaxy Watch 4/5/6 to Google Pay on watches in **regions shipping
+without Samsung Pay preinstalled**.
 
 Watches that ship without Samsung Pay end up with a long-press
 shortcut that they can't remap. This app makes the shortcut
 launch Google Pay instead.
 
 **NOTE:** Requires a watch reboot to take effect.
 
-[XDA Developers](https://forum.xda-developers.com/t/spaytogpay-remap-samsung-pay-long-press-shortcut-to-google-pay-on-watches-in-regions-shipping-without-samsung-pay.4459229/)
+**NOTE:** On Wear OS 4.0 (One UI 5), the user needs to grant the
+app the SYSTEM_ALERT_WINDOW permission in order for it to be able
+to launch the Google Pay app from the background.
+
+`adb shell pm grant com.samsung.android.samsungpay.gear android.permission.SYSTEM_ALERT_WINDOW`
+
+[XDA Developers](https://forum.xda-developers.com/t/spaytogpay-remap-samsung-pay-long-press-shortcut-to-google-pay-on-watches-in-regions-shipping-without-samsung-pay.4459229/)